PABITRA KUMAR MAITRA (1 November 1932 - 5 September 2007)

Biog. Mew. Fell. INSA, New Delhi 35 201-226 (2009)

PABITRA KUMAR MAITRA (1932-2007) Elected Fellow 1980

FAMILY BACKGROUND AND EARLY EDUCATION ABITRA KUMAR MAITRA was born on November 1,1932 in Majdia village in PNadia district of West Bengal. He was the fourth chld of mother Snehalata and father Sukurnar Chandra Maitra. Sukumar Chandra Maitra, a graduate, served in the Da rjeeling Himalyan Railway and was stationed in Kurseong. Pabitrats grand father, Amblka Charan Maitra, was an advocate, while lus uncle was a professor in Dajeeling Government College. His maternal uncle, Jyotirmoy Lahiri, was the principal of Ballygunj Government School at Calcutta and retired as the Assistant Director of Public Instructions of West Bengal, while the second maternal uncle, Karunamoy Lahiri was the professor of ophthalmology in the Calcutta Medical College. Maitra's elder brother, Sunil was a member of the West Bengal Civil Service and retired as a Secretary to the Government of West Bengal. His younger brother, Ashok has a master's degree in structural enpeering from the University of Minnesota and has retired from the National Thermal Power Corporation as its General Manager. He has three sisters. As a child Maitra went to a school in Kurseong, then moved over to Krishnanagar Anglo Vernacular School closer to his birth place, when he was seven years old, and studied there till his matriculation examination. Maitra's school days were not very pleasant. First, as Maitra had narrated during lus interview by Dr. Indira Chowdhury (Preferred citation: Maitra, PK Oral hstory interviews conducted by Indira Chowdhury, Kolkata and Bangalore, India, 2 April - 12 June 2003, TIFR Archive), "The school did not have a very glorious academic history. 1 will tell you why, because 1 appeared for the Matric examination in 1948 and my brother passed out in 1942 with a District Scholarship, with first division of course. In between for 6 years there was not even a single first division in the school." Then, in 1943, during the months of May to November, there was a very severe famine in Bengal, when an estimated three to four million people died of starvation. People fled from their villages to escape the famine, but no food was available in the towns either. People were dying on the streets (Ghosh, 1944). Maitra had described to Dr. Chowdhury, "I have many snapshots in my mind of that famine. I don't want to recollect those". Then in 1947 there was communal carnage in Calcutta and its repercussions spread to the neighbouring towns including Krishnanagar. Maitra recounted Chowdhury, "It doesn't matter whether anything happens or not. Fear i Biographical Memoirs causes all kinds of psychological trauma" and fourteen year old Maitra was the only male member in the house then. AnyGay, Maitra passed the matriculation examination in first division in 1948. Because of financial constraints, Maitra's parents planned to enroll him as an apprentice in the nearby Kanchrapara Railway Workshop. But as he reminisced to Dr. Chowdhury, Maitra said, "No, I want to go to college. So I kept on singing the same song. I want to go to college, without really knowing what college was like. But I thought that I would like to study a little bit more." His parents yielded and Maitra took admission to the Intermediate Science course in Krishnanagar Government College. The gold bangles of Maitra's mother had to be pawned to borrow money to pay admission fee. As Maitra had confessed to Dr. Chowdhury, "It hurt me inside immensely. Because I knew what gold meant to my mother. Because generally that's the capital exchanged when the next daughter is going to be married. So it was as if 1 was actually foreclosing one marriage or something. I felt guilty." "And then one day somebody told me that 'you have made it on the scholarship list.' See scholarship was not like these days. Scholarship was very rare, few, in fact very few. So I didn't expect anything. First thing I did was to tell my friend 'don't tell anybody in the house.' I went to the accounts office, 'when is money coming?' I just wanted to get the money because I wanted to release my mother's bangles." "Every day I used to go and the man would say, 'Arrey! You have come again, no go back, you don't come,' and one day they said, money has come." "So I went home with so much money 1 had never seen in my life." "See that's a joy, 1 could not share with anybody because I didn't want everybody to know." "That was my real moment of achievement actually. It made me feel very big. I was able to clear mother's ornaments without any help. This is the only story 1 had of my life (laughter)." Maitra did very well in the Intermediate Science examination, got a scholarship and came to Presidency College, Calcutta in 1952 to study BSc with Chemistry Honours. His favourite subject was Physics, but his elder brother advised him to stud) Chemistry in view of the financial uncertainty of the family and the presumed better chance of a chemistry graduate to get a job. As Maitra mentioned to Dr. Chowdhury, "Our future was totally undefined. We had no idea of the fact that I would go for M.Sc. and then a PhD. After that I will come to America and then to Tata Institute. The excellence of all the institutions that 1 was going to taste. I never had any inkling of that. So events happened and I floated along with these". It was in Presidency College that we met Maitra for the first time. As our friend, Asish Kumar Pain, a retired member of the West Bengal Civil Service has said, "Pabitra .. was short, fair in appearance with a strong jaw and a pair of bright eyes". Dr. Anadi .; Nath Chatterjee, formerly professor and head of the Department of Biotechnol Jadavpur University, Calcutta, remembers him as "the boy with golden voic was always sought after in our 'adda' sessions at CoUege Street Coffee H Pabitra Kurnar Maitra remember him as a very thorough student, but never a book worm, who did all the practical experiments neatly and seriously. After graduating from Presidency College, some of us, including Maitra, joined the Department of Applied Chemistry at the University College of Science and Technology, Calcutta and completed the three year MSc Tech course. Maitra's elder brother had supported him. Maitra had opted for Biochemistry as his special subject and had chosen vitamin 812 production by Streptomyces olivaceus as his research project. He then joined the laboratory of the late Professor Sailesh Chandra Roy in the same department for his PhD work on the metabolic processes in Streptomyces oliz~accus. Maitra's classical paper on 'Pathways of glucose dissimilation by Streptotrzyces olivaceus', which was published in The Journal of Biologcal Chemistry in 1959, comprised only a part of his PhD work. He stayed on with glucose dissimilation all his life. Maitra was a great help to the other students in the laboratory and exhibited even at that early stage considerable ability to guide research. He, in fact, was Professor Roy's trusted lieutenant. 1 remember, I had written a paper on my research work on mitochondria1 metabolic processes and had gven it to Professor Roy for correction. The next day Maitra came up to me with my manuscript to ask for some clarification, Professor Roy has asked Maitra to do the preliminary checlung. As long as Maitra was around, this was the routine. Ananda Mohan Chakrabarty, now Distinguished University Professor of the University of Illinois College of Medicine at Chicago recalls, "I first met Professor Maitra, popularly known as Pabitrada in the student circle, when I was an MSc student at the Calcutta University. As part of the M.Sc. degree, I had to do research on a topic of biochemical relevance and submit a thesis. My mentor, Professor SC Roy, directed me to work under Pabitrada's supervision, since he just finished his PhD thesis under Professor Roy. I was assigned to work on the biosynthesis of vitamin 812 by a bacterium Streptomyces olivaceus. Pabitrada was a prolific researcher and a demanding supervisor. Even though he finished his thesis work, he spent long hours in the laboratory and expected me to do the same. He was meticulous, dedicated, friendly, helpful and considered time spent outside the lab a total waste. His careful and constant supervision allowed me to publish a couple of papers in journals such as Bioclzimica et Biophysics Acta and Biochemical Journal".

PROFESSIONAL CAREER AND SCIENTIFIC CONTRIBUTIONS In the autumn of 1960, Dr. Maitra joined the Johnson Research Foundation for Biophysics at the School of Medicine of the University of Pennsylvania, Philadelphia, USA, as a post-doctoral fellow. As Ronald W Estabrook, then Associate Professor in the Johnson Foundation, now Ashbel-Smith Emeritus Professor of Biochemistr Cecil and Ida Green Chair in the Biomedical Sciences at the University of Biographical Memoirs Southwestern Medical Center at Dallas, USA recalls, "Under the dynamic leadership of a brilliant physical chemist/electronic engineer named Britton Chance (BC), the Johnson FoundationUF) was a world-famous fountainhead for research on hemeproteins involved in biological electron-transport reactions, in particular reactions of ATP synthesis by mitochondria. The JF was a beehive of activity with a continual stream of visiting scientists from all parts of the world that came to the JF to test their favorite reaction using the specialized spectrophotometric instruments developed by BC for measuring the role of cellular oxidation-reduction pigments in a variety of cellular functions. As I recall, it was the Fall of 1960 when Brit appeared in my lab with a short, young man from Calcutta, India named Pabitra Maitra. Pabitra had applied for a postdoctoral research fellowship to the Johnson Foundation and had been accepted to work with the great Britton Chance. But Brit was overwhelmed by the sea of visitors who contmually appeared to work with him-so his policy was to reassign new post-doctoral fellows to junior faculty in the department who had the responsibility to oversee and supervise their research training. It was my turn - and that is how Pabitra ended up working in my laboratory." "How generous fate is to some individuals. Both Pabitra and I gained from our collaboration as we developed into a research team." "Pabitra was assigned the challenge of applying the fluorometric method that worked so well with isolated rat liver mitochondria to the study of yeast. The advantages were numerous. Most important was the ease of reproducibly preparing large amounts of yeast for study, thereby avoiding the need to daily kill any animals and prepare liver mitochondria. But the disadvantage was the increased turbidity of yeast associated with a greatly reduced content of respiratory chain components - in particular pyridine nucleotides. Experiments were initiated by Pabitra by studying the metabolism of ethanol by bakers yeast obtained at the local grocery store. These experiments worked. Pabitra was soon testmg other substrates, other alcohols, other conditions of growth of the yeast; any variable that could be tested. Pabitra was a talented and dedicated laboratory scientist. The path was then set for his subsequent very successful career. But there were many more questions to answer and many new experiments to do. Could the fluorometric technique be used to study bacterial metabolism? Could one develop highly sensitive analytic methods to measure the individual fluorescent contributions of NADH separate from NADPH? Could a fluorometric method be developed to measure the cellular content of ATP, ADP and AMP by couphg assay reactions to the formation of NADH or NADPH. Could tlus principle be extended to measure other chemical intermediates formed during metabolism (such as glycolytic intermediates), using coupled reaction systems developed by others? The research program for Pabitra was rapidly expanding - but Pabitra was up to the task and systematically worked on each of these problems during the three years he worked in my laboratory. I stdl have a mental pic Pabitra sitting cross-legged on an old, rickety stool in front of the fluor patiently assaying samples." Pabitra Kurnar Maitra "One more story is appropriate. Pabitra was a generous and sharing person. He had a friend from India named Amal Ghosh who was worlung in the Biochemistry Department of the Medical School examining the role of inositol phosphates on fatty acid metabolism. Amal was testing this reaction using an inositol-deficient strain of yeast as his experimental system. But he was only having limited success in showing an effect. Pabitra convinced and helped Amal to use the fluorometer to monitor changes in reduction of the yeast's pyridine nucleotides during the metabolism of glucose. The very first experiment revealed the damped sinusoidal oscillations of metabolism that captured so much attention in the subsequent decade." "Many new and exciting hndings resulted from the work of Pabitra. The methods he developed have been taken up and used by researchers in laboratories around the world. At a young age, he made an impact on science - he made a difference in how we think about metabolism. Much more can be said about the many scientific contributions made by Pabitra Maitra." "As one travels through life you meet individuals that make a lastmg impression. Pabitra K Maitra was such an individual in my life." Dr. Maitra's work established the suitabhty of yeast as a model system for the study of the regulation of cellular metabolism. In addition to working with yeast in the laboratory of Dr. Ronald Estabrook, Dr. Maitra also found time to work with other systems like ascites tumor cells, electrophorus and pigeon heart mitochondria, which were of interest to Professor Britton Chance. His work with ascites tumor cells led to the important revelation of multisite control of biochemical pathways. Dr. Maitra demonstrated that after the electrical discharge by the electric eel, it was the glycolytic pathway that provided the major source of energy and not the popularly believed tricarboxylic acid cycle. Professor Chance summed up his impression of Dr. Maitra in one sentence, "a remarkable researcher who was absolutely reliable, friendly, lund and good natured". Professor David Lloyd, now Head of Wcrobiology in Cardiff University in Wales, United Kingdom, who was in Johnson Foundation then, recollects, "Pabitra, who could be guaranteed to do the types of experiments that no-one else could do so thoroughly, was in great demand. His speciality was to be able to take and arrest the metabolism of a long series of samples from an incubation mixture, and then ("at leisure!") analyse them for coenzyme or metabolite concentrations. These were the pioneering days of the studies of metabolic control mechanisms, and the field of energy metabolism was one of the first to receive detailed attention. The demands on the experimenter were challengmg. Pabitra's papers on glycolytic control in b yeast, ascites cell cultures, and also with bacterial suspensions reveale extremely high turnover rates of metabolic intermediates. Thus this work necessitated a rare breed of investigator who could obtain interpretable data. To have witnessed such fast action, high speed dexterity, and precision of small volume measurement was in itself an education. There would be at least three ice buckets with several dozen grease-pencil-numbered test tubes (these were the days before the invention of the 'magic' marker felt-tip pen or 96-well plastic plates) containing the perchloric acid solution used for arrestirig metabolism. A quick cigarette (these were also the days of untamed personal freedoms) and he would be away, as fleet- of-foot, hand, and eye as a trained athlete. The result might be a sequence of samples at 3 second intervals over 5 minutes without any missed points or outliers; analysis employed spectrophotometric, or more sensitively, fluorometric determinations using coupled enzyme reactions that resulted in generation of NADH or NADPH. And this every day of the week! Levels of adenine nucleotides, each and every intermediate of glycolysis and of the tricarboxylic acid cycle could and would be measured. Together with his Indian colleague Dr Amal Ghosh, Pabitra discovered oscillations in glycolytic intermediates for the first time. John Higgins established the theoretical principles of feedback control to explain these exciting and unexpected experimental observations and David Garfinkel used an analogue computer to model the system. Thus Britton Chance's group were instrumental in initiating a whole new area of insights into the control of energy metabolism. Pabitra, with his customary modesty when asked, would always undersell his own personal role in this epochal advance." Dr. Maitra's work not only elicited admiration in the academic circle, the corporate world also becdme interested in him. The chemical @ant Dupont invited him in 1963 to their head office at Delaware and requested him to give a talk on his work. As Dr. Maitra had described to Dr. Indira Chowdhury, " The reaction to my talk was very good, everybody praised it sky high and appreciated it. After that the Head, who was also a scientist, called me and said, 'Well done, Dr. Maitra, I have something for you. We should spend some time, we will go for lunch together. 1 wanted to tell you that we are interested in you.' I asked, 'What do you mean by that?' He said, 'It would be very nice if you agree to join this company, Dupont.' But I wanted to come back to India, there was no other reason. My people, my friends, my relations, they are much more precious to me. I am very fond of my brother. Yes, because I did not go there to stay. That was very clear in my mind and I really wanted to come back. I wanted to meet my seniors, my parents, my uncles." Dr. Maitra returned to India in 1963 and joined the Molecular Biology Unit in the Tata Institute of Fundamental Research. As Professor Obaid Siddiqi recollects, "I got a letter from Dr. Pabitra Maitra and also one from Britton Chance, his professor

at the Johnson Foundation. Chance wrote a nice letter about him. Maitra was d ' something very different from what we were interested in. He was interest reaction kinetics. He worked with glycolysis - he was measuring enzyme rea Pabitra Ktirnar Maitra in the glycolvtic pathway. That was his expertise. 1 knew people in Philadelphia who had spoken well of him. There was a lady, Mildred Cohn, who was a biochemist. She had told me that he was enthusiastic and energetic. Mildred Cohn's husband, Henry Primakoff was a physicist, and he thought well of him. So 1 knew that people were recommending him. So Maitra was the first one that we offered an Associate's position to in the Institute. It was in the first year." In TIFR, Dr. Maitra continued with glucose dissimilation in yeast. His main concern throughout the rest of his life has been to understand how metabolic .flux was regulated and homeostasis maintained in cells even when the levels of the enzymes and the substrates of the glycolytic pathway were substantially modulated. His first paper from TIFR was on glucose flux in yeast. Dr. Maitra reported that the entry and the utilization of glucose by yeast were oscillatory. "lt appeared as if the entire glycolytic pathway behaved as a unit, presumably the flux through each segment was sort of interdependent." The duration of the stimulated and inhibited periods ranged from 10 to 45 seconds at 25.C. He inferred that the entry into and utilization of glucose was controlled in yeast by feedback through some product(s) of glucose metabolism. In 1966 Dr. Maitra received an invitation from Dr. Britton Chance to visit Johnson Foundation again for a year as Visiting Assistant Professor to continue and conclude the work that he initiated there during 1960-1963. He accepted the invitation and collaborated with Dr. Ronald W Estabrook on elucidating control mechanisms operative during oxidation of acetaldehyde and alcohol in yeast. He had also collaborated with GF Williamson and studied thermal activation of glycolysis and population synchronization of yeast. DEF Harrison had then come from England to Johnson Foundation with his favourite bacteria, Klebsiella nerogenes. Dr. Maitra helped him study control of respiration and metabolism in growing K. aerogenes. This time Dr. Maitra was in Johnson Foundation only for nine months, but his short visit resulted in the publication of six excellent papers including one invited paper on "The fluorometric determination of mitochondria1 adenine and pyridine nucleotides" in Methods in Enzymology. Dr. Maitra returned to TIFR in April 1967 and went back to his search for the controlling element operative during glucose dissimilation in yeast. 1 met him in the autumn of 1967 in his small laboratory which contained only one work bench. I also met there Dr. Maitra's Laboratory Assistant Zita Lobo, a quiet young girl. Dr. Maitra was very excited about his research project and his conviction about the possible presence of a feed-back control element in the glycolytic pathway. He looked into the first step of dissimilation, which should be phosphorylation, but no glucolanase has been known in yeast. To eliminate hexokinase, Dr. Maitra mutagenised nitrosoguanidine and selected with 2-deoxyglucose for fructose negativit glucose positivity. He could indeed purify glukokinase to homogeneity fro Biographical Memoirs mutant strain and characterize it. He, however, failed to notice any striking control property of the glucolunase. Dr. Maitra acknowledged Zita Lobo's 'able technical assistance' in the glucokmase paper. Subsequently, he changed gears and went on to study the tune course of the synthesis of each of the dozen glycolytic enzymes in yeast after addition of glucose or galactose, as well as of their disappearance on removal of the sugars. A clear lunetic heterogeneity was elicited, suggesting multiplicity of regulation elements. In this paper, whch was published in the Journal of Biological Chemistry, Zita Lobo was justly elevated to the level of a coauthor, she was not even a graduate then. Dr. Maitra and Zita Lobo subsequently identified glucose 6-phosphate to be the inducer of aldolase, triose phosphate isomerase, glyceraldehyde 3-phosphate dehydrogenase, phosphoglycerate lunase, phosphoglycerate mutase, enolase and pyruvate lunase, while mannose 6-phosphate and glucose 1-phosphate were the inducers of hexohase and phosphoglucomutase. Around this tune two students joined Dr. Maitra, first Shankar La1 Chakrabarti and then Meher H. Irani. Dr. Maitra would gve his students a free hand to choose their research problem. As Avtar K Handa, now Professor of Molecular Genetics at Purdue University, recollects, "On 1st August 1970, I walked into the Molecular Biology Unit and had my first encounter with PKM, who was acting head in the absence of Obaid. I distinctly remember to have asked him what 1 shall work on for my PhD. His answer was 'If I know that, I will hire a technician not a PhD student, especially since there is no dearth of funds at TIFR. The goal of the TIFR graduate program is to transform young bright mind into thinker who will make novel contribution in the coming years to whatever field they select. Go to library and read what ever you feel interested in. We will have another conversation in couple of months'." Both Shankar and Meher chose to work with Esckerickia coli. Shankar worked on streptomycin resistant mutants that had lesion in the STRA locus, which determines the structure of the ribosomal protein P10. Shankar and Dr. Maitra discovered changes in the structure and lunetic properties of enzymes of the glycolytic pathway that were synthesized on the mutant ribosomes. Meher wanted to isolate mutants of Esckerickia coli that would have lesions in the structural genes of the enzymes of the glycolytic pathway. One problem was the impermeability of E. coli cell membrane to the phosphorylated intermediates of glycolysis, but tlus could be circumvented by adding a non-phosphorylated product farther down in the chain. The other problem was that the enzymes of this pathway catalyzed both glycolysis and gluconeogenesis. Dr. Maitra had recognized this problem, "how to get such mutants in a physiologcally bidirectional pathway? One has to provide for metabolites not only 'after' but also 'before' 'the genetic block. A mutant blocked at the phosphoglycerate kinase for example, would be unable to grow on pyruvate, glycerol or glucose, but should be able to grow on a mixture of pyruvat glycerol". Meher followed this strategy and isolated Esckerickia coli mutants d in glyceraldehyde 3-phosphate dehydrogenase, glycerate 3-phosphokina Pabitra Kurnar Maitra enolase. She used glycerate as the source of carbon above the block and succinate as one below, as she found that glucose was toxic to the mutants, possibly because it severely repressed P-galactosidase synthesis. Physiological and genetic characterization of the mutants revealed two important points. (i) The gluconeogenic requirement of a growing culture of E. coli was only one-twentieth of its total catabolic and anabolic needs. (ii) The structural genes of the enzymes of the glycolytic pathway were not linked in E. coli. Meanwhile, on invitation from Methods in Enzymology, Dr. Maitra wrote an article on "Glucokinase from Yeast". In the laboratory, he contmued with yeast with the assistance of Zita Lobo. They obtained yeast mutants of the glycolytic pathway by adopting the same strategy as he did with E. coli. Pratima Sinha, now a professor in Bose Institute in Kolkata, joined him as a student and characterized yeast mutants producing structurally altered pyruvate lunase. Zita Lobo and Dr. Maitra worked out the genetics of the two hexokinases PI and P2 of yeast and also demonstrated that these were the only two enzymes that could phosphorylate fructose in yeast, while these two hexolunases and also a glucokinase could phosphorylate glucose. They constructed three sets of yeast mutant strains having any one of these three enzymes and found out that glucokinase appeared to be catalyzing nearly half of the glucose flux in wild type yeast. Pasteur effect was elicited by mutants having glucokinase alone. While worlung on the genetics of glucose phosphorylation in yeast, Lobo and Maitra discovered that a direct selection of mutants lacking glucose- phosphorylating enzymes was resistance to 2-deoxyglucose. Lobo and Maitra worked down the sequence of steps in glycolysis and isolated an yeast mutant lackmg in phosphoglucose isomerase and characterized the mutant genetically. The mutation appeared to be in the structural gene of the enzyme. Then they moved on to phosphofructokinase, the rate determining step in glycolysis, and presented evidence of the existence in yeast of distmct genes (PFKI and PFK2) for the two subunits of phosphofructokinase. They presented evidence to conclude that the allosteric properties of the yeast soluble phosphofructohase was derived from the interaction of these two gene products. Professor Maitra's students, Medha Nadkarni and Latika Parmar have obtained mutant alleles of the gene PFK2 that altered the sensitivity to ATP inhibition of the soluble yeast phosphofructokinase. One of the alleles made the enzyme sensitive to micromolar concentrations of ATP. Mutations in the gene PFK2 converted the allosteric enzyme into a Michaelis enzyme. Next they made the interesting observation, a double mutant with lesions in both PFKl and ZWFl (the gene for glucose 6-phosphate dehydrogenase- the first enzyme in the pentose phosphate pathway, also known as hexose monophosphate shunt pathway), could still grow in glucose and glycolysis continued to operate. They resolved the apparent inconsistency by discovering a hitherto undescr enzyme, the particulate phosphofructokmase 11, that also catalysed the forma fructose 1,6-diphosphate from fructose 6-phosphate and ATP. Phosphofructo Biographical Memoirs 11, in contrast to the soluble phosphofructokinase, was not inhibited by ATP, but was inhibited by fructose 1,6-diphosphate. Prof. Mai tra's student Medha Nadkarni found that two unlinked nuclear genes PFKZ and PFlO were involved in the production of phosphofructolunase 11. It was the same PFK2 that coded for the regulatory subunit of the soluble phosphofructokinase. The PFK2 gene product was soluble and was produced constitutively, while the PFK3 gene product was particulate and was produced only in the exponential phase of growth in the presence of glucose. Intragenic revertants of PFK2 mutants confirmed that the PFKi gene determined the regulatory properties of the soluble enzyme and also the catalytic activity of particulate phosphofructokinase. Medha Nadkarni and Latika Parmar found that all 20 mutations in PFK2 they checked, had lost the activity of the particuldte phosphofructokinase 11, while the activity of the soluble phosphofructokinase I was affected only indirectly in that it was detected only at very low concentrations of ATP. In between, Professor Maitra looked at the reversibility of glycolysis in yeast. By using mutants blocked at a number of glycolytic steps, he concluded that the metabolic flow during reversal of glycolysis took place along the Embden-Meverhof pathway in the reverse direction bypassing pyruvate kinase and fructose 6- phosphate kinase. The rate of reversal in the span phosphoenol pyruvate to fructose 1,6-diphosphate approached 40 pmol of 3-carbon units per minute per gn7 of wet cells. Professor Maitra spent a year during 1982-1983 as a visiting professor in the University of Illinois College of Medicine at Chicago. Professor Ananda M Chakrabarty, Distinguished University Professor, University of Illinois College of Medicine at Chicago, who has long experience of worlung with Psetido~~ro~zas, recollects, "I had received a grant from NIH to work on alginate synthesis by Pseudonzonas aeruginosa that causes deadly infections in the lungs of cystic fibrosis patients. I knew nothing about alginate, an exopolysaccharide produced by infecting P. aeruginosa. Desperate, I pleaded with Pabitrada to come to my rescue and spend a sabbatical year at the University of Illinois at Chicago, guiding me through the complex ways that bacteria use sugar residues to make polysaccharides. ~eluctantl~, but graciously and always wifing to help out younger people, Pabitrada did arrive in my lab as a visiting professor. The year of 1982 was the hallmark of my research productivity. Pabitrada worked day and night, kept a technician Rita Vanags and a graduate student A1 Darzins on their toes, published several papers and made sure that not only my NIH grant got renewed, but it should receive appropriate recognition from NIH, which it did in the form of a MERIT award (a renewal for 10 years). After a year, Pabitrada left, but his emphasis on scientific excellence, his demand for imagination coupled with hard work and his love for science rem in our hearts for ever. I have been lucky in my life to have Pabitrada as my and friend and greatly benefited from his advice, guidance and constant Pabitra Kumar Maitra supervision. 1 will cherish his memory for the rest of my life." Professor Maitra's approach was straight forward. Generate Pseudomonas aeruginosa mutants deficient in enzymes involved in sugar metabolism and check whether the synthesis of algnic acid, which is a polymer of selectively acetylated D-mannuronic and L-guluronic acids, is affected. A phosphoglucose isomerase mutant did not synthesize algnic acid from mannitol, nor did a glucose 6-phosphate dehydrogenase mutant synthesize algnic acid from mannitol or glucose. Mutants lacking the Entner- Doudoroff pathway dehydrase or aldolase failed to produce alginic acid from mannitol, glucose, or gluconate, as a 3-phosphoglycerate kinase or glyceraldehyde 3-phosphate dehydrogenase mutant failed to produce from glutamate or succinate. The primary role of the Entner-Doudoroff pathway enzymes in the synthesis of alginic acid from glucose, mannitol, or gluconate and the role of glyceraldehyde 3-phosphate dehydrogenase reaction for the synthesis from gluconeogenic precursors such as glutamate became obvious. .'.. mutant of deficient in fructose 1,6-bisphosphate aldolase did not allow appreciable alginate formation from glucose and gluconate, but allowed alginate synthesis from mannitol and fructose. This suggested that glucose and gluconate must be converted to fructose 1,6-bisphosphate via the Entner-Doudoroff pathway enzymes and fructose 1,6-bisphosphate aldolase before algnate could be synthesized. Professor David Lloyd, Head of Microbiology in Cardiff University in Wales, United Kingdom was a long time admirer of Prof. Maitra and had been requesting him to visit his laboratory. Professor Maitra obliged him in 1985 and spent 4 months in his laboratory. There he made use of mass spectrometry to show that mutations in the phosphofructolunases alter the in vivo control characteristics of glycolysis in yeast. In Professor Maitra's laboratory in TIFR, work on other aspects of phosphofructokinase continued. His student, Archana G Cayatri demonstrated genetic complementation of soluble phosphofructolanase activity in yeast mutants and R Mehta with Zita Lobo's help cloned the yeast PFKl and PFK2 genes. Zita Lobo and another student of Prof. Maitra, lnderpreet Kaur Sur demonstrated that an yeast strain lacking activity of PFKl and PFK2 brought about 30-fold overexpression of the particulate phosphofructokinase, when transformed with multiple copies of PFK2. This overexpression was independent of PFKl and multiple copies of PFK2 appeared to be the only requirement for overproduction of the particulate phosphofructolunase. On the other hand, overproduction of the soluble phosphofructokinase required multiple copies of both PFKl and PFK2. They also found that yeast mutants laclung the particulate phosphofructokinase defined at least five unlinked genes, PFK2, PFK3, PFK4, PFK5 and PFK6. A structural role of PFK2 was again indicated. Mutations in the other four had pleiotropic effects. They later demonstrated that PFK4 and PFK6 also affected the activity of the so Biographical Memoirs phosphofructokmase I during growth on alcohol. Thus the hkbetween the soluble and the particulate enzyme was manifested by as many as three genes. Professor Maitra then ventured into other enzymes involved in glucose dissimilation in baker's yeast. His student, Anindya Slnha looked at induction of enzymes of the oxidative pentose phosphate pathway in yeast by glucono-delta- lactone, while V Raghuram and S Velmurugan worked with the yeast pyruvate decarboxylase. V Raghuram cloned and sequenced PDC2 and discovered that PDC2 coded for a novel transcription factor required for the expression of PDCZ and PDC5, two of the three structural genes for pyruvate decarboxylase. S Velumurugan isolated extragenic suppressors of PDC2 and identhed three genetic loci that could suppress the PDC2 phenotype. Professor Maitra's work spanning more than three decades on the genetic and biochemical dissection of E. coli and yeast glycolytic pathway had fetched him international recognition and made him and his group pioneers in the field of microbial glucose dissirmlation. As Professor David Lloyd of Cardiff recollects Professor Maitra's early days in TIFR, "No one had succeeded in isolating a mutant organism defective in an enzyme of the glycolytic pathway. With hs young technician, Zita Lobo, Pabitra was beping work which was to become a consuming passion for the rest of his life and which was to earn him a second platform for international acclaim. The genetic control of sugar metabolism sat squarely upon and complemented his earlier metabolic work." Professor Lloyd contmues, "Pabitra's ideas almost always worked. He was an intuitive scientist; and his feeling for his enzymes, his yeast, and his science was truly remarkable. And Satpal Singh wrote: 'It was joy, sheer joy that feehg of romance, excitement and enthusiasm about the work they were doing. This is the feeling that makes science so unique.' Pabitra's legacy is not only a scientific one, his huge personality and many kindnesses live on in our hearts." 'The Molecular Biology Unit at TIFR was an integral part of Professor Maitra's life. The biographical memoir of Professor Maitra would be incomplete without some mention of the Unit. 1 quote Professor David Lloyd of Cardiff, "The Molecular Biology Unit of the Tata Institute was a centre of dynamism! And the dedication and enthusiasm of its members was highly reminiscent of the Philadelplua laboratory. The intensity of scientific endeavour at the Tata Institute made for a stimulating -t environment for all concerned. However, in many ways it was more warmly . c. accommodating than its more aggressive American counterpart, with a more relaxed & J' and gentlemanly ambience, where the current form of Tendulkar and Ganguly was as likely to excite comment as the latest advances in PNAS. The residence of many of the postgraduates in the Colony made a highly coherent society of scholars and was daily reinforced by close contacts with academic staff at mealtimes in one three canteens on-site in the Institute. A central figure in hssociety was P Pabitra Kurnar Maitra who was on first-name term with everyone, from the porters and workshop engmeers, the office staff and from the kitchen workers all the way up to the Director." Professor Lloyd remembers Professor Obaid Siddiqi saying during the International Symposium in Contemporary Genetics '93, "You will have noticed that Pabitra and I, although only one year different in age, are very different phenotypes. He is very small, but very excitable and swlft to move and make decisions, whereas I am very tall, slow and somewhat lazy! The result is that together we have complementation!" Professor Maitra retired from TIFR in 1994 and joined IIT, Bombay. Professor PJ Bhat has provided his recollection. "The erstwhile Biotechnology Center at IIT Bombay became an independent unit in early 1990s, with few faculty members. Biology as a branch of science was alien to IITB, llke other IITs. Therefore, we requested Professor Maitra to be a part of this center. Initially, he was reluctant, but then finally agreed with the condition that he would bring in his own funding. He became a CSIR Emeritus Professor and was in IIT for close to a year. He was staying in a barely furnished flatlet, all alone. He was totally independent in his personal life as he was in his professional life. Professor Maitra distinguished himself as a true scientist in that, science was a way of life for him than a means to get recognition. It is exactly because of this reason, he was one of the few well respected scientists. Although hsassociation lasted only for a short while, it boosted our morale in many ways". On invitation from Agharkar Research Institute (ARI) at Pune, Prof. Maitra joined as 'Professor SP Agharkar Professor' after spending about a year at IIT, Bombay. Professor Surendra Ghaskadbi recollects, "Pabitra interacted very closely with several scientists and most of the doctoral students at ARI. He took keen interest in all areas of biology. His unfailing presence and active participation in seminar talks and journal club presentations was indeed a bonus. He had an inquisitive mind and asked deceptively simple questions that often opened an entirely new line of inquiry. Students spent hours with him, especially in the late evenings, when he talked to them about music, football, Presidency College, 'Sandesh' and TIFR. Pabitra got himself involved fully in anything and everything he did and was totally spontaneous in his actions. Whle his short temper became evident in a flash at a stupid 'scienMic' argument, a Sach Tendulkar straight drive instantly brought tears to his eyes. As a member of the Research Advisory Committee of ARI, he urged everyone to do better and was more than happy to be of help. Whenever possible he introduced some of us lesser known scientists of ARI to the elite. This not only allowed us to overcome our apprehensions, but resulted in forming lasting friendship with many colleagues all over India". In ARI, Professor Maitra worked with the marine methanogen, Methanococcoides methylutens, as bacterium was of interest to the Agharkar Research Institute. He was the f determine quantitatively the actual in vivo steady state concentrations of dif Biographical Mernoirs metabolites and enzymes of glycogen metabolism of a methylotrophic marine methanogen. Professor Maitra was in Agharkar Research Institute for about four and a half years. As he had mentioned to Dr. Indira Choudhury, "Agharkar Institute was an interesting experience for me. It would have been nicer if 1 was there a little longer ."

MARRIAGE Professor Maitra married Zita Lobo. Zita Lobo had joined Professor Maitra as a Laboratory Assistant in 1965, when she was only a matriculate. She knew nothing of Science, but she was a very attentive student. Professor Maitra taught her all the nuances of experimentation and Zita transformed herself into an excellent technician. She continued her studies while working in the laboratory and did BSc, MSc and PhD under Professor Maitra's supervision. Simultaneously, she silently got herself promoted to the position of Professor Maitrafs dependable and indispensable collaborator. As Dr. Shobhona Sharma, then a student and now a Professor in TIFR, remembers, "PKM iind Zita Lobo constituted an unusual team. PKM would think of an experiment and the next day Zita, who had green fingers, would be found performing the experiment and presentmg PKM with the results. This positive feedback loop worked wonders for them, but left a disgruntled lot of several of us in the Molecular Biology Unit who could never match this". Veronica Rodrigues and K Vijayraghavan, both Professors in the National Centre for Biological Sciences at Bangalore, wrote, "Maitra and Lobo developed their collaborative efforts into one that genuinely shared talents and became mutually dependent. Their teamwork at the bench and in analysing their data was legendary. Maitra's ability to dissect tetrads and map mutants was invaluable as was Zita's ability to generate all combinations of strains and pick the mutant needle from the haystack." But all this was only at the level of Science. Dr. Man Mohan Johri, formerly Professor and Head of the Molecular Biology Unit at TIFR recalls, "It appears that PKM had not thought of marriage until very late in life. He may not have realized the extent to which Zita Lobo had become dependent on him for emotional and academic inputs (or needs)." Some realization possibly dawned on both the parties when around 1985 Zita Lobo went to the University of Washington, USA on a Fulbright Fellowship. Zita did not complete the one year term of the Fellowship, but came back early to TIFR. Professor Maitra himself had later mentioned in a different context during his interview with Dr. Indira Chowdhury, "This was in the mid '80s or something like that, may be the late '80s, I was getting sort of emotionally close to Zita". But neither of them thought of marriage. Professor Maiha told Dr. Chowdhury, "Had there been no Mala (Mala and her husband, Deepak Mukerjee were close friends of Dr. Maitra), there would have been no marriage for me. She was the one. She asked me, 'what are you about Zita?' I said 'no plan'. 'After retirement you will go away?' I said, 'ye Zita?' she asked. Then I thought about it. No, honestly, 1 didn't have any inte Pnbitrn Krlrnar Maitra just [thought] life would go on like this". "So I told Zita, 'Shall we marry?' And you know what she said? She said 'We are going on well nahi?"' Finally, they did get married on 2nd May in 1997.

AWARDS AND HONOURS Professor Pabitra Kumar Maitra was admitted to the fellowship of the Indian National Science Academy in 1980. He was also a Fellow of the Indian Academy of Science, Bangalore. He was presented the INSA JC Bose medal in 1992 and the Om Prakash Bhasin award in 1996. He was a Member of the International Cell Research Organization's panel of experts on Energy Metabolism and a Member of the Editorial Board of the Iournal ofMoleculnr nlzd Cell~~larBiocl~e~nistry.

EXTRA CURRICULAR QUALITIES Pratima Sinha (now professor in Bose Institute, Kolkata) and Anindya Sinha (now in National Institute of Advanced Studies, Bangalore), who were students of Professor Maitra, have written, "PKM enjoyed his science thoroughly". Very true, but Professor Maitra enjoyed other things also. He enjoyed listening to classical music, both western and Indian. He enjoyed singng, particularly Rabindra Sangeet (Tagore songs). He had a melodious voice and his Bengali pronunciations were immaculate, his Tagore songs were thus a real treat. His younger brother Ashok tells me that while in Eden Hindu Hostel of Presidency College, Calcutta, he shared the stage with his idol, the legendary singer Hemanta Kumar Mukhopadhyay, who was all praise for him. Professor David Lloyd of Cardiff recalls, "The 60tll shared birthday party, Januarv 14th -16Lhl1993, of the founder members of the Molecular Biology Unit at TIFR, (0baid Siddiqi and Pabitra Maitra) produced a meeting (International Symposium in Contemporary Genetics '93) with a very impressive roster of highly -. distinguished and internationally renowned attendees. At the end, Pabitra concluded his thank-you ovation by brealung into song. It came as a revelation to me that this tiny Bengali had a rich baritone voice of tremendous power. His songs were so touching, that the audience couldn't get enough, and the encores went on and on." Professor Maitra, however, did not have any formal training in singing. Professor Maitra enjoyed being in the midst of nature. As Dr. Sunil Kumar Chattejee, now Professor at the University of Cincinnati, Ohio, who was in University of Pennsylvania in 1966, recalls, "Pabitrada particularly appreciated nature and would often invite me along on his outings. We would walk around fields and woods and lakes aimlessly, and he would regularly burst into song when no one else was around. He was actually a quite good singer. Most of the time he would sing the songs of Tagore, but he would also be so suddenly inspired by nature that he would start to recite various poems." Mr. Susim Mukul formerly Chairman, Board of Directors and Managing Director of Hindustan reminisced, "I remember one occasion in Matheran when we were wallung d Biographical Memoirs the bus stand in the pre-dawn hours, we missed the turn of the road and lost our way in the forest. Pabitra was entranced by the play of bright moonlight on the trees casting dappled shadows and he was eloquent on the beauty of nature, oblivious of the more urgent task of finding our way back again." Professor PJ Bhat of IIT, Bombay stated, "Apart from science, Professor Maitra was deeply interested in music, literature, arts and he was an avid nature lover." Professor Surendra Ghaskadbi of the Agharkar Research Institute, Pune recollects, "Pabitra was as interested in yeast genetics as he was in the grey hornbills that frequent the trees of ARI." Professor Maitra enjoyed the company of children. We moved to the Indian Agricultural Research Institute in Delhi in 1969 and Pabitra used to be our guest whenever he would visit Delhi. His main attraction was our 7 year old son, who would look forward to Pabitra kaku's (Pabitra uncle's) arrival. Dr. Maitra and our son would converse continuously on all kinds of subjects including football. Pabitra was a staunch supporter of Mohon Bagan Club of Calcutta and we were equally staunch supporters of the arch rival East Bengal Club. Whenever Mohon Bagan Club would defeat East Bengal Club in a football match, Pabitra's letter would come from Bombay enquiring about the well being of our son! In January 1973, I attended the one month long Molecular Genetics workshop conducted in TIFR by Professor Luigi Gorini and his wife Ana Marie Toriani. My whole famdy accompanied me and Pabitra and our son had a real gala time. Our two year old daughter also enjoyed Pabitra kaku's (Pabitra uncle's) company immensely. Dr. Shobhona Sharma of TIFR remembers; "PKM was an extremely affectionate person in his heart and that exuded out when he encountered children. He would immediately gwe up his work and turn his full attention to them. To my children, as also for several others in TlFR community, he is fondly remembered as 'lighter-uncle', as he would fascinate them for hours with his lighter (and indulge in teaching them to play with fire!)." Professor Ronald Estabrook of Johnson Foundation recollects, "I remember bringing Pabitra to my home in Swarthmore (a suburb of Philadelphia) at Christmas time. It had started snowing that afternoon. When we arrived home for dinner we were greeted by our four children who had a sleigh in hand and were already dressed in their heavy outdoor clotlung, prepared for testing the slope in front of our house. Pabitra joined them, so we got him a warmer coat, hat and gloves. 1 still have a vision of him laughing and shouting as he rode the sleigh down the lull. Also, that day was special since Pabitra made his hrst snowman with our daughter Jill." Mr. Susim Mukul Datta, formerly of Hindustan Lever, has rightly observed, "Pabitra had a wonderful way with children. When 1 look back over the years, I feel that this mutual attraction was the result of Pabitra's ability to understand children's logic, which differs from the adult logic, and to empathise with them. He never recourse to his age and experience and remained highly accessible to child wonder, as Professor Sunil Kumar Chatterjee of the University of Cincinna Pabitra Kumar Maif-ra mentioned, " Pabitrada's favourite book of poetry was actually Abol Tabol, which is a collection of children's poems by Sukumar Roy." Professor Maitra enjoyed good food, Bengali sweets and good drinks.

LAST DAYS The last several years of the life of Professor Pabitra Kumar Maitra have been riddled with misfortunes. First, he had a fall in 1996 leading to injury in his hips and backbone. As a result, he found it difficult to stand or sit for extended period. In 1998 he was afflicted with painful Herpes, which affected hs ability to stretch the leg. 1 met him in 1999 when he and Zita visited his younger brother, Ashok in Delhi. He was the same old spirited self, smiling and entertaining, gving no clue of his pain. In September 2000, however, tragedy struck, Zita complained of feeling out of breath, when climbing stairs. Her chest X-ray revealed extensive lesions in the lung. She had cancer. On October 6, 2000 Zita breathed her last. It was a terrible blow to Professor Maitra. As he told Dr. Indira Chowdhury later, "Without Zita 1 was completely alone. It was only a personal thing. But this is what makes a man, after all I am an individual with my own past. So I couldn't stay anywhere without Zita except with my family. So, I went back to Calcutta. I decided not to do any more science, because it was very painful for me. Zita and I were so closely knit in our science, it is very difficult to know who did what. So it was very difficult for me. So I decided that enough was enough." Professor Maitra could go back to the Agharkar Research Institute at Pune, but he did not, he went to Kolkata and spent the rest of his Me with his younger sister Khula's family. Khuki took care of him like his second mother. His two elder sisters also stayed nearby and provided the feehg of being close to his family. I used to talk to him over the telephone on the first day of Baisakh (Bengali New Year, around mid April) and on Bejoya Dashami (Dussera day, around mid October) every year. He would be very happy to chat with me and would enquire about our children by name. As years passed by, the conversation became shorter, as if he did not have anything to talk about. Around the middle of 2005, it was diagnosed that Professor Maitra has been afflicted with Alzheimer's disease. When I called him on the first day of Baisakh of the Bengali year 1414 (April 15,2007), he did not recognize me and did not to talk to me. His memory had faded, but he would still sing Rabindra Sangeet as correctly and as melodiously. As Mr. Asish Pain recollects, "One afternoon I invited him to our residence. His health was broken and mind distracted, but his voice was still captivating. He regaled us with a number of songs. The last song he sang was Tagore's 'Ei kathati mane rekho' (Please remember these words). Yes, I'd ever remember Pabitra, the friend and the singer, till I depart." Professor Maitra's former student, Anindya Slnha recalls, "My family and I went to visit last April, by which time Alzheimer's had already set in. He was unable to reco Biographical Memoirs us at all. I told him how I had learnt so many songs from him-and I began to sing 'Shanto nodi-ti...' (the quiet river), a song whch I am sure many of you will remember. I, however, inadvertently sang it wrongly 'Chotto nodi-ti ...' (the tiny river). PKM's eyes lit up the way I always remembered them; he corrected me and said that the word was 'shanto' not 'chotto'!" Professor Maitra suffered from a cerebral stroke on 19 August, 2007 and subsequently went into coma. He passed away at 00:30 hours of September 5, 2007. The news of Dr. Maitra's demise spread fast, the former students of TIFR immediately joined in the mourning and exchanged e-mails the very same day. Following are some representative ones. "It is appropriate to pay a tribute to a great teacher today-Teachers day, September 5. I am deeply indebted to PKM for shaping and enriching my life, and would vouch for the generality of this statement for many of those fortunate to have interacted with him." - Shobhona Sharma Tata lnstitute of Fundamental Research, Bombay "Sad news. We all have our fond memories of PKM. Jibes would fly between PKM and certain other Bengalis after East Bengal- Mohun Bagan football matches, and for our TIFR football matches too PKM was often there to cheer and discuss strategy. If there's a Happy Hunting Ground, I hope it has a fine football field." -Johannes Manjrekar Maharaja Sayajirao University of Baroda "I know his mind is adr& from us all, may be also from his beloved yeast and its sugar metabolism, but perhaps, and I really hope that it is so, his music still plays on in'hs mind." - Rana (Anindya Sinha) National lnstitute of Advanced Studies, Bangalore "Dear Professor Maitra, wherever you are now, I wish you peace and happiness. And I want you to know that you are still alive withm the recesses of the minds of so many of us who have had the good fortune to come in contact with you. And if, while. interacting with you, any of us did imbibe even a small bit of your strength of character, your undying passion for Science, your indomitable spirit that made you fight all the misfortunes life had to offer -then we have been blessed." - Archana Maharaja Sayajirao University of Baroda "I have been a silent admirer of PKM. He has been a great scientist and teacher. His continuous hard work has been noticed and it had impressive influence on many students including me. Yes it is most appropriate to pay a tribute to a great teacher today-Teachers Day, September 5." - Ghanshyam Centre for Cellular and Molecular Biology, Hy Pabitra Kumar Maitra "PKM is gone. This is sad indeed and reminds us the programmed destiny of life. However, death does not take away the person from us. So PKM lives in all of us, in our success, in our love of all good things and in being a decent human being. I can never forget his srnihg face. Maut ko Kuchh Na Ma Chand Anaasir Ke Siwa Zindag Apni Jagah Hai, '~aheenAayei Na Gayei. Death can not take away, perchance the order of some elements. Life goes on in its course, it hardly moves with such vicissitudes. Let us all celebrate the We of Dr. Pabitra Kumar Maitra.". - Shahid Siddiqui University of Chicago School of Medicine, Chicago "I hope PKM knew how we all felt about him. I was just Wingof teachers day today and PKM certainly stands out in my mind as someone who has influenced me in a strong way. He was so much a part of our lives in TIFR-- his warmth, his zest for life, hs big heart, his love for children, the disciphe he instilled in us, hs enthusiasm for science and research. I will never forget hs strong emotions- especially when curled up in that chair in the yeast lab, with eyes closed he recalled a favourite song or some food or 'notoon gur--that nectar of the gods ...heaven on earth'. While I do feel sad he is no more, I am happy that he suffers no more and is at peace. I do hope he has joined Zita, I really like Shahid's sentiment - that with our memories and in ways we have been influenced, both he and Zita will continue to live on in each one of us. I am glad to have known him and like Shahid says lets celebrate his life even as we grieve that he is no more." - Sunita DeSousa Astra Zeneca India Pvt Ltd., Bangalore "I am deeply saddened by the passing away of PKM. Professor Maitra was a person of profound convictions and left a deep impression that till today influences my thought process. As we all know that interplay of at least two components shape our actions, thought process and future; First genes (Mendelian genetics) and second environmental influence (Lamarcluan evolution). All of us have no choice (at least until today) as far as the first component is concerned, but some of us can be fortunate to have right set of the second one. PKM provided the second component to those of us who came in contact with him, and benefited us from his wisdom, thoughtfulness and kindness. Thus even though PKM has left us; his legacy will stay alive for a long time. May his soul rest in peace!" -Avtar K Handa Purdue University, West Lafayette "I am very sad to hear this news today even though time has to come for one and all. I recall many discussions PKM used to have with me about glycolysis mutants, as I was always in the same room as he, doing my hexolunase assays on the spectrophotometer. He showed me, with how much zeal one does science. I do with Shahid and others the theme that we celebrate his life as a great teach Biographical Memoirs scientist today. He had been an inspiration to so many young minds. His memories will conhnue to inspire us all. May his soul rest in peace." - Bondada Subbarao University of Kentucky, Lexington "We are really sad PKM has passed away. I use to enjoy having many discussions with him on various topics other than just science. My wife, Benaifer, and me always remember our TIFR days as the best days of our life. May PKM's soul rest in peace. A big tribute to a great teacher on this teacher's day, September 5." - Rasheed Mistri Cornart Lithographers and ASAP Designs It would be relevant here to quote from the obituary written by Professor Pratima Sinha (Bose Institute, Kolkata) and Dr. Anindya Sinha (National Institute of Advanced Studies, ,Bangalore) which appeared in Current Science, "To his colleagues and students, PKM will always be remembered for his undying passion for science, a remarkable strength of character, a wry sense of humour and, of course, his indomitable spirit that made him fight all the misfortunes life had in store for him. Although he did not care for awards and honours, deriving pleasure solely from his scientific pursuits, he never failed to inspire others to ackueve higher levels of excellence and integrity, be it in science or in other spheres of life. In many ways, PKM has changed our lives forever."

The author is grateful to Dr Indira Chowdhury, Archivist of TIFR, for making available to the complete transcript of the interview with Professor Maitra, which she conducted between April 2 and June 12 of 2003. He is also grateful to Professors PJ Bhat, Sunil Kumar Chatterjee, Ananda Mohan Chakrabarty, Ronald W Estabrook, Surendra Ghaskadbi, Man Mohan Johri, David Lloyd, Dulal Panda, B Jagadeeshwar Rao, Veronica Rodrigues, Shobhona Sharma, Obaid Siddiqi, Pratima Sinha and Krishnaswamy Vijayraghavan for their very valuable inputs. He is equally grateful to ~rBfessorMaitra's college friends, Professor Anadi Nath Chatterjee, Mr Susim Mukul Datta, Mr Asish Kumar Pain and Mr. Rabindra Narayan Kundu and Professor Maitra's younger sister Mrs. Anjali Bagch, younger brother, Mr. Ashok Maitra and nieces Uma and Suma for their help and valuable inputs. He is grateful to the former students of TIFR Professors Sunita Desousa, Archana G Gayatri, Avtar K Handa, Johannes Manjrekar, Rasheed Wstri, Sahid Siddiqui, Anindya Smha, Bondada Subbarao and Ghanshyam Swarup for permitting him to quote from their emails that they had exchanged immediately after the demise of Professor Maitr author is grateful to Professors Arun K Attri, Rani Gupta, Rajendra Prasad Srinivasan for their help in accessing some of the publications of Professor Pabitra Kurnar Maitra Description of the Bengal famine of 1943 is based on Kali Charan Ghosh (1944) Famines in Bengal: 1770-1943, Indian Associated Publishing Co., Calcutta. HIRENDRA KUMAR DAS, FNA B-9/6324, Vasant Kunj New Delhi-110070 Phone: 01 1-26895424 E-mail:hirendas@hotmail. com

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