The 1993 Dexter Award Address

Bull. Hist. Chem. 17/18 (1995) 1 THE 1993 DEXTER ADDRESS Thomas Burr Osborne and Chemistry ph S. rtn, Yl Unvrt I count it an honor to appear before a meeting of the Division of the History of Chemistry. My talk will deal with the place of Thomas Burr Osborne in the histori- cal development of protein chemistry (1). To begin with, I will describe briefly the state of that field in the late 1880s and the circumstances that brought Osborne into it. I will then try to summarize his work in relation to that of his principal contemporaries. Finally, I will speak about Osborne's qualities as a leader of his research group. Osborne was a Connecticut Yankee who spent his entire life in New Haven. He was born there in 1859, went to Yale for his undergraduate and graduate studies, and studied chemistry there with William Gilbert Mixter. He was the only son of a prominent New Ha- ven banker, who wanted young Osborne to join him in the Second National Bank, but at Yale he had become interested in analytical chemistry. A year after he had received his Ph.D., Osborne joined the staff of the Con- necticut Agricultural Experiment Station, located in New Haven, where he headed the Biochemical Laboratory until 1928. He died in New Haven in the following year (2). When Osborne came to the Station in 1886, its di- rector was Samuel William Johnson [1830-1909], whose daughter Osborne married in the same year (3, 4). His first publications dealt with such matters as soil analy- T. B. Osborne sis, but in 1888, at the suggestion of his father-in- law, Over a thirty-year period, beginning in 1862, he turned to the chemistry of plant proteins, and pub- Ritthausen published an extensive series of papers on lished his first paper on the subject in 1891. The stimu- the preparation and characterization of proteins from lus provided by Johnson was a consequence of the fact plant seeds. When he began this work, the only amino that he was an assiduous reader of the European litera- acids thought to be generally present in proteins were ture on agricultural chemistry, and had come to admire glycine, leucine, and tyrosine. Ritthausen added glutamic the contributions of Heinrich Ritthausen [1826-1912] acid and aspartic acid to the list and showed that hy- (5). During the 1850s, Johnson had worked in Leipzig drolysates of proteins which Liebig had considered to and had met Ritthausen at that time. 2 Bull. Hist. Chem. 17/18 (1995) be identical btn differed greatly in their content entific work as a crystallographer, had stated in 1883 of these amino acids. Along with others of his time, (8): "You know that the most complex molecules of plant Ritthausen crystallized the seed globulins from several chemistry are the albuminoid substances. You also know plants. The procedures were very simple: a sodium chlo- that these immediate principles have never been obtained ride solution was allowed to cool slowly, or dialyzed in a crystalline state. May one add that apparently they against water, whereupon well-developed crystals ap- cannot crystallize." Pasteur, by that time the great healer, peared. Some physiological chemists considered such apparently did not know of the work of Ritthausen and crystalline proteins to be important. For example, in the others on crystalline proteins from plant seeds, or chose 1887 (first) edition of his textbook, Gustav von Bunge to ignore it. After egg albumin had been crystallized by wrote (6): "The analysis and investigation of the pure Franz Hofmeister [1850-1922] in 1889, the noted crys- protein crystals and the various products of their cleav- tallographer Arthur Wichmann examined them, and age should provide the groundwork for all of physiologi- wrote ten years later (9) that "There is scarcely a crys- cal chemistry." Apparently Johnson shared this view, but talline substance which, like a sponge, soaks up dissolved it should also be noted that his decision to encourage substances as does albumin." And in 1913, the great Osborne to engage in basic research on the chemistry of organic chemist Emil Fischer [1852-1919], of whom I plant proteins reveals vision and courage in the face of shall have more to say shortly, wrote about crystalline the down-to-earth objectives of the Experiment Station, proteins as follows (10): "... the existence of crystals namely to provide reliable chemical analyses of com- does not in itself guarantee chemical individuality, since mercial fertilizers. isomorphous mixtures may be involved, as is frequently At Johnson's suggestion, therefore, Osborne under- the case in mineralogy for the silicates." Indeed, for most took to repeat and extend Ritthausen's studies, and be- of the German organic chemists of Osborne's time, the tween 1888 and 1901 Osborne's chief aim was the iso- proteins were included among the natural products which lation and purification of the proteins of plant seeds. Be- they chose to denote as Schmiere. ginning with oat seeds, from which he obtained crystal- Also, at the turn of the century, leading biochem- line avenin, he proceeded to study the proteins of over ists had turned to the study of proteins as colloids, which 30 different seeds; indeed, bottles containing samples Thomas Graham had defined as noncrystalline and non- of his preparations are still tucked away in the vault of diffusible substances, and they preferred to apply the the Johnson Laboratory at the Experiment Station. Dur- new physical chemistry to the study of adsorption phe- ing this early phase of Osborne's work, his aim was to nomena exhibited by proteins. It would seem, therefore, prepare what he considered to be pure proteins, and his that Osborne chose to disregard prevalent opinion and, principal criterion for purity was a reproducible elemen- as a well-trained analytical chemist, to begin his work tary analysis for carbon, hydrogen, nitrogen, and sulfur. on proteins by single-mindedly pursuing his goal of pu- Accordingly, he set himself the task of checking the dis- rifying them by crystallization and of drawing conclu- cordant reports in the earlier literature on the elemen- sions about their identity or individuality from their el- tary composition of the seed proteins. As he expressed it ementary composition and their solubility properties. in 1892 (7): In 1892, Osborne reported his findings on the crystalline globulins from six different kinds of seeds - Bra- The fact that these proteid substances can be artifi- zil-nut, oat-kernel, hemp-seed, castor-bean, squash-seed, cially crystallized is not only interesting in itself, but and flax-seed. He concluded that the first two globulins is important as presumably furnishing a means for making preparations of undoubted purity which will are distinct proteins, and different from the other four, afford a sure basis for further study of their proper- which appeared to him to be the same protein. Two years ties. The contradictory statements made by various later, Osborne found the seed globulins from wheat, investigators, not only in regard to the properties and maize, and cotton to have the same elementary compo- composition of these bodies but also in respect to the sition as the four seemingly identical proteins; and he value of the methods of solution and separation which considered the seven kinds of seeds to contain the same have been employed hitherto, render an exact knowl- globulin, which he named "edestin." By 1903, how- edge of all the facts relating to these substances a mat- ever, he was obliged to revise this opinion, but in the ter of the highest scientific and practical importance. mean- time he continued to amass data on many other Osborne's confidence in crystallization as a means of seed proteins, including the alcohol-soluble prolamines preparing pure proteins was not shared by some of his such as zein and gliadin. In those intervening years, im- contemporaries. Thus, Louis Pasteur, who began his sci- portant advances had been made in protein chemistry, Bull. Hist. Chem. 17/18 (1995) and Osborne changed the direction of his research pro- haps best known for his synthesis of polypeptides. In gram accordingly. December 1905, he wrote to his teacher Adolf von The most important of these advances was the ad- Baeyer as follows (13): dition of many amino acids to the list of regular protein On January 6th I will present a lecture at the Chemi- constituents. Those added between 1880 and 1903 in- cal Society summarizing my work on amino acids, cluded the basic amino acids lysine, arginine, and histi- polypeptides and proteins, and then early next year I dine , as well as phenylalanine, cystine, alanine, valine, will publish the collected papers in the form of a book. isoleucine, proline, hydroxyproline, and tryptophan (11). The material has grown splendidly and there is much In particular, the finding that the basic amino acids form detail in it. Recently I have also prepared the first sparingly-soluble salts with phosphotungstic acid led crystalline hexapeptide and hope to obtain a match- Walter Hausmann, a student in Hofmeister's laboratory, ing octapeptide before Christmas. Then we should to develop in 1900 a method for the determination of be close to the albumoses....My entire yearning is directed toward the first synthetic enzyme. If its the partition of the nitrogen in acid hydrolysates of pro- preparation falls into my lap with the synthesis of a teins among the so-called ammonia-nitrogen, basic-ni- natural protein material, I will consider my mission trogen, and nonbasic nitrogen fractions. Osborne seized fulfilled. upon the Hausmann

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