TEXTBOOK OF for Dental Students

TEXTBOOK OF BIOCHEMISTRY for Dental Students

D. M. VASUDEVAN MD, FRCPath Principal, Amrita School of Medicine Amrita Institute of Medical Sciences and Dean, Faculty of Medicine Amrita Vishwa Vidyapeetham (Deemed University) Cochin-682 026, Kerala E-mail: [email protected]

and

SREEKUMARI S MBBS, MD Professor, Department of Biochemistry Jubilee Mission Medical College Trissur, Kerala

JAYPEE BROTHERS MEDICAL PUBLISHERS (P) LTD New Delhi Published by Jitendar P Vij Jaypee Brothers Medical Publishers (P) Ltd B-3 EMCA House, 23/23B Ansari Road, Daryaganj New Delhi 110 002, India Phones: +91-11-23272143, +91-11-23272703, +91-11-23282021, +91-11-23245672, Rel: 32558559 Fax: +91-11-23276490, +91-11-23245683 e-mail: [email protected] Visit our website: www.jaypeebrothers.com Branches  2/B, Akruti Society, Jodhpur Gam Road Satellite Ahmedabad 380 015 Phones: +91-079-26926233, Rel: +91-079-32988717, Fax: +91-079-26927094 e-mail: [email protected]  202 Batavia Chambers, 8 Kumara Krupa Road Kumara Park East, Bangalore 560 001 Phones: +91-80-22285971, +91-80-22382956, Rel: +91-80-32714073, Fax: +91-80-22281761 e-mail: [email protected]  282 IIIrd Floor, Khaleel Shirazi Estate, Fountain Plaza Pantheon Road, Chennai 600 008 Phones: +91-44-28193265, +91-44-28194897, Rel: +91-44-32972089, Fax: +91-44-28193231 e-mail: [email protected]  4-2-1067/1-3, 1st Floor, Balaji Building, Ramkote Cross Road Hyderabad 500 095, Phones: +91-40-66610020, +91-40-24758498, Rel:+91-40-32940929, Fax:+91-40-24758499, e-mail: [email protected]  No. 41/3098, B & B1, Kuruvi Building, St. Vincent Road Kochi 682 018, Kerala, Phones: 0484-4036109, +91-0484-2395739, +91-0484-2395740  1-A Indian Mirror Street, Wellington Square Kolkata 700 013, Phones: +91-33-22451926, +91-33-22276404, +91-33-22276415, Rel: +91-33-32901926 Fax: +91-33-22456075, e-mail: [email protected]  106 Amit Industrial Estate, 61 Dr SS Rao Road Near MGM Hospital, Parel, Mumbai 400 012 Phones: +91-22-24124863, +91-22-24104532, Rel: +91-22-32926896 Fax: +91-22-24160828, e-mail: [email protected]  “KAMALPUSHPA” 38, Reshimbag Opp. Mohota Science College, Umred Road Nagpur 440 009 (MS) Phones: Rel: 3245220, Fax: 0712-2704275 e-mail: [email protected]

Textbook of Biochemistry for Dental Students © 2007, DM Vasudevan, Sreekumari S All rights reserved. No part of this publication should be reproduced, stored in a retrieval system, or transmitted in any form or by any means: electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the authors and the publisher.

This book has been published in good faith that the material provided by authors is original. Every effort is made to ensure accuracy of material, but the publisher, printer and authors will not be held responsible for any inadvertent error(s). In case of any dispute, all legal matters are to be settled under Delhi jurisdiction only.

First Edition : 2007 ISBN 81-8061-891-9

Typeset at JPBMP typesetting unit Printed at Ajanta Offset and Packaginges Ltd. With humility and reverence, this book is dedicated at the lotus feet of the Holy Mother, Sri Mata Amritanandamayi Devi

"Today's world needs people who express goodness in their words and deeds. If such noble role models set the example for their fellow beings, the darkness prevailing in today's society will be dispelled, and the light of peace and non-violence will once again illumine this earth. Let us work togethr towards this goal"—Mata Amritanandamayi Devi

Preface

The medical community of India has warmly received the "Textbook of Biochemistry for Medical Students", edited by us. It was originally published in 1995, and now running the 4th edition. We were getting persistent requests from teachers of dental courses that a concise version of the Textbook is necessary for catering their needs. In order to satisfy this continued demand, we are now presenting this Textbook of Biochemistry for Dental Students. This book is prepared after consulting the sylabi of Dental courses of various universities. As there are slight variations on the emphasis given by different universities, we have tried to incorporate all the facts prescribed in all those curricula. So, some students may find some chapters unnecessary for their immediate purpose. But a general textbook of this nature has to satisfy the needs of all students. The important points are made into bold letters, so that students can grasp the subject easily. Moreover, the facts are given in point-wise (with numbers), so as to aid easy memorisation. There are two sets of undergraduate students; majority wants only a pass. For them, the essentials of Biochemistry are given in ordinary font. A small group of students aspire for distinction; for them a bit more advanced knowledge is given in small prints. Students just before the examination can skip the tiny letters, but these areas will also become important later in their pursuit of knowledge. Those who are interested to get more facts may consult our Textbook of Biochemistry for Medical Students. A question bank, given in the end of the book contains essay questions, short notes and viva voce type questions . These questions are compiled from the question papers of various universities during the last decade. These questions will be ideal for students for last-minute preparation for examinations. The first author desires more interaction with faculty and students who are using this textbook. All are welcome to communicate at his e-mail address We extend our thanks for the enormous help rendered by Dr. Ananth N. Rao and Dr. R. Krishnaprasad in preparation of this book. We also thank Shri Jitendar P Vij, Chairman and Managing Director, Jaypee Brothers Medical Publishers Pvt Ltd., New Delhi and his associates for their active support in making this publication possible. A textbook will be matured only by successive revisions. We hope that this first edition will be friendly to the students and be attractive to the teachers. Now this is in your hands to judge. “End of all knowledge must be building up of character”—Gandhiji.

DM Vasudevan Sreekumari S

Contents

1. Subcellular Organelles and Cell Membranes...... 1 Nucleus, Endoplasmic reticulum, Golgi apparatus, Lysosomes, Peroxisomes, Mitochondria, Cell membranes: Composition, Fluid Mosaic Model, Transport mechanisms, Facilitated diffusion, Ion channels, Ligand gated channels, Voltage gated channels, Active transport, Sodium pump, Uniport, Symport, Antiport.

2. Amino Acids and ...... 7 Classification based on structure, Classification based on metabolic fate, Classification based on nutritional requirement, Properties and reactions, Iso-electric point, Decarboxylation, Transamination, Peptide bond, Color reactions of amino acids and proteins, Structure of proteins, primary, secondary, tertiary and quaternary structures, Primary structure of insulin, Structure-function relationship, iso-electric pH, Precipitation reactions, Denaturation of proteins, Heat coagulation, Classification of proteins, Quantitative estimation of proteins. 3. Enzymology ...... 20 Classification, Co-enzymes, Mode of action of enzymes, Active centre, Kinetics, Michaelis constant, Activation, Competitive inhibition, Noncompetitive inhibition, Allosteric inhibition, Key enzymes, Feedback inhibition, Covalent modification, Specificity of enzymes, Iso-enzymes, Clinical Enzymology, Lactate dehydrogenase, Creatine kinase, Enzyme patterns in diseases, Enzymes as therapeutic agents. 4. -I: Chemistry, Digestion and Absorption of Carbohydrates ...... 33 Monosaccharides, Glucose, Fructose, Mannose, Galactose, Stereoisomers, Epimers, Reactions, Benedict's reaction, Osazone, Glycosides, Amino sugars, Deoxy sugars, Disaccharides, Sucrose, Lactose, Maltose, Polysaccharides, Starch, Glycogen, Cellulose, Mucopolysaccharides, Digestion, Absorption, Glucose transporters. 5. Carbohydrates - II: Metabolic Pathways of Glucose ...... 46 Embden-Meyerhof pathway, Glycolysis, Regulation, Cori's cycle, BPG shunt, Fate of pyruvate, Gluconeogenesis, Glycogenolysis, Glycogen synthesis, Glycogen storage diseases, Hexose monophosphate shunt pathway, Glucose-6-phosphate dehydrogenase deficiency. 6. Carbohydrates - III: Regulation of Blood Sugar and Diabetes Mellitus ...... 62 Regulation of blood glucose, Glucose tolerance test, Impaired glucose tolerance, Alimentary glucosuria, Renal glucosuria, Reducing substances in , Insulin, Glucagon, Diabetes mellitus, Diabetic keto acidosis, Chronic complications, Glycated hemoglobin. 7. Carbohydrates - IV: Metabolic Pathways of Other Sugars ...... 74 Fructose , Hereditary fructose intolerance, Fructosuria, Galactose metabolism, Galactosemia, Metabolism of alcohol. x  Textbook of Biochemistry for Dental Students 8. Saliva and Dental Caries ...... 79 Composition of saliva, Inorganic and organic components, Functions of saliva, Salivary enzymes, Functions of salivary proteins, Composition of teeth, Collagen, Mineralisation, Dental caries, Plaque, Microbiological organisms and dental caries, Sucorse and dental caries, S.mutans, Prevention of caries, Fluoride, Fluorosis. 9. - I: Chemistry ...... 88 Classification of lipids, Classification of fatty acids, Saturated fatty acids, Unsaturated fatty acids, Polyunsaturated fatty acids, Triglycerides, Classification of compound lipids, Phospholipids, Lecithin, Phospholipases, Cephalin, Plasmalogens, Sphingolipids, Nonphosphorylated lipids, Sphingomyelin, Cerebrosides, Gangliosides, storage diseases, Essential fatty acids, Eicosanoids, Prostaglandins, 10. Lipids - II: Metabolism of Fatty Acids ...... 96 Digestion and absorption of lipids; Beta oxidation, Energetics, Oxidation of odd chain fatty acids, De novo synthesis of fatty acids, Synthesis of triglycerides, Metabolism of adipose tissue, Hormone sensitive lipase, Liver adipose tissue axis, Fatty liver, Lipotropic factors, Ketone bodies, Ketogenesis, ketolysis, Ketosis. 11. Lipids - III : Cholesterol, Lipoproteins and Cardiovascular Diseases...... 110 Steroids, Structure of cholesterol, Biosynthesis of cholesterol, Plasma lipids, Transport of lipids, Lipoproteins, Chylomicrons, LDL, HDL, Lp(a), Free fatty acid, Non-esterified fatty acids, Hypercholesterolemia, Plasma cholesterol, Atherosclerosis, Coronary artery disease. 12. Amino Acid Metabolism ...... 122 Digestion of proteins, Absorption of amino acids, Catabolism of amino acids, Formation of , Transamination, Oxidative deamination, Disposal of ammonia, cycle, Disorders of urea cycle, Hepatic coma, Blood urea, Glycine, Creatine, Creatinine, Methionine, Transmethylation reactions, Cysteine, Glutathione, Homocystinurias, Phenylalanine, Tyrosine, Melanin, Catecholamines, Phenylketonuria, Alcaptonuria, Albinism, Tryptophan, Nicotinic acid, Serotonin, Melatonin, Indican, Hartnup's disease, Histidine, Histamine. 13. Plasma Proteins ...... 141 Serum electrophoretic pattern in normal and abnormal states, Albumin, Transport proteins, Acute phase proteins, Ceruloplasmin, Immunochemistry, Structure of immunoglobulins, Vari- ability, Classes of immunoglobulins, IgG, IgM, IgA, IgE, Multiple myeloma, Plasmacytoma, Bence-Jones proteinuria. 14. Citric Acid Cycle, Biological Oxidation and Electron Transport Chain ...... 147 Citric acid cycle reactions, Significance of TCA cycle, Amphibolic role, Regulation, Integration of metabolism, Primary, secondary and tertiary metabolism, Biological oxidation, High energy compounds, Organisation of electron transport chain, Flow of electrons, Oxidative phosphorylation, Chemi-osmotic theory, ATP synthase, Inhibitors of ATP synthesis. 15. Heme and Hemoglobin ...... 157 Hemoglobin, Biosynthesis of heme, Porphyria, Shunt bilirubin, Catabolism of heme, Plasma bilirubin, Hyperbilirubinemias, Hemolytic jaundice, Hepatocellular jaundice, Obstructive jaundice, Differential diagnosis of jaundice. Structure of hemoglobin, Transport of gases, Oxygen dissociation curve, Isohydric transport of carbon dioxide, Chloride shift, Fetal hemoglobin (HbF), Hemoglobin derivatives, Carboxy hemoglobin, Methemoglobin, Hemoglobin variants, Sickle cell hemoglobin (HbS), Thalassemias, Myoglobin, Anemias. 16. Vitamins - I : Fat Soluble Vitamins (A, D, E, K) ...... 170 Vitamin A, Role in vision, Wald's visual cycle, Vitamin D, Calcitriol, Vitamin E, Vitamin K. 17. Vitamins - II : Water Soluble Vitamins (Thiame, Riboflavin, Niacin, Pyridoxine,

Pantothenic Acid, Biotin, Folic Acid, Vitamin B12 and Ascorbic Acid) ...... 177 Thiamine (B1), Beriberi, Riboflavin (B2), Niacin, Pyridoxine (B6 ), Pantothenic acid, Biotin, Folic acid, Folate antagonists, Vitamin B12, Ascorbic acid (Vitamin C), Scurvy. Contents  xi 18. Mineral Metabolism ...... 189 Calcium, Homeostasis, Parathyroid hormone, Calcitonin, Hypercalcemia, Hypocalcemia, Phosphorus, Sodium, Potassium, Iron, Absorption, Iron deficiency, Hemochromatosis, Copper, Ceruloplasmin, Iodine, Zinc, Heavy metal poisons, Lead. 19. Energy Metabolism and Nutrition ...... 200 Calorific value, Respiratory quotient, Basal metabolic rate (BMR), Specific dynamic action, Requirements, Dietary carbohydrates, Dietary fiber, Nutritional importance of lipids, Nutritional importance of proteins, Essential amino acids, Nitrogen balance, Biological value of proteins, energy malnutrition (PEM), Marasmus, Kwashiorkor, Obesity, Prescription of diet. 20. Detoxification and Free Radicals ...... 209 Oxidative reactions, Reductive reactions, Hydrolysis, Conjugation, Free radicals, Reactive oxygen species, Generation, Damage, Free radical scavenger systems, Lipid peroxidation, Anti-oxidants. 21. Acid-base, pH, Electrolyte and Water Balance ...... 214 Acids and bases, Henderson-Hasselbalch equation, Buffers, Buffer capacity, Buffers of body fluids, Respiratory regulation of pH, Renal regulation of pH, Disturbances in acid-base balance, Metabolic acidosis, Metabolic alkalosis, Respiratory acidosis, Respiratory alkalosis. Body water compartments, Electrolyte concentration of body fluid compartments, Regulation of sodium and water balance, Renin-angiotensin system. 22. Muscle and Supportive Tissue Proteins ...... 224 Collagen, Contractile proteins, Actin, Myosin, Troponin, Muscle contraction. 23. Nucleotides; Chemistry and Metabolism ...... 228 Purine bases, Pyrimidine bases, Nucleosides, Nucleotides, Biosynthesis of purine nucleotides, Regulation of synthesis, Degradation of purines, Uric acid, Gout, Lesch-Nyhan syndrome, Synthesis of pyrimidine nucleotide, Regulation, Degradation of pyrimidine. 24. DNA—Deoxyribonucleic Acid: Structure and Replication ...... 236 Structure of DNA, Watson-Crick model, Supercoiling of DNA, Replication of DNA, DNA polymerases, Replisome, Okazaki fragments, Repair mechanisms, Xeroderma pigmentosum, Inhibitors of DNA replication. 25. Transcription and Translation ...... 242 Ribonucleic acid, mRNA, RNA polymerase, Transcription, Initiation of transcription, Elongation of transcription, Termination of transcription, Post-transcriptional processing, Introns and exons, Reverse transcriptase, tRNA, rRNA, Ribosomes, Protein biosynthesis, Genetic code, Translation, Initiation of translation, Elongation of translation, Termination of translation, Post-translational processing, Inhibitors of protein synthesis, Mitochondrial DNA. 26. Control of Gene Expression...... 250 Mutations, Point mutation, Frame shift mutation, Mutagens, Cell cycle, Regulation of gene expression, Operon concept, Repression, Depression, Lac operation. 27. Recombinant DNA Technology and Gene Therapy...... 255 Application of recombinant DNA technology, Restriction endonucleases, Vectors, Plasmids, Chimeric molecules, Cloning, Transfection, Selection, Expression vectors, Gene library, Human Genome Project, Gene therapy, Vectors for gene therapy, Retroviruses, Polymerase chain reaction (PCR). 28. AIDS and Cancer ...... 259 AIDS transmission, Natural course of the disease, Laboratory analysis, Virus, Replication, HIV genes and gene products, of AIDS, Prevention, Cancer, Etiology, Chemical carcinogens, Antimutagens, Oncogenic viruses, Oncogenes, Proto oncogene, Oncosuppressor genes, Oncofetal antigens, Tumour markers, Alpha-fetoprotein, Carcinoembryonic antigen. xii  Textbook of Biochemistry for Dental Students 29. Methods of Separation and Assay of Biological Compounds...... 265 Electrophoresis, Immuno-electrophoresis, Southern blot, Northern blot, Western blot, Radio immunoassay (RIA), Enzyme-linked immunosorbent assay (ELISA), Colorimeter, Photo electric colorimeter. 30. Liver and Function Tests ...... 272 Serum bilirubin, Classification of jaundice, Bile acids and bile salts, Serum enzymes as markers of hepatobiliary diseases, Gastric function, Hydrochloric acid secretion, Assessment of free and total acidity. Kidney Function Tests: Formation of urine, Functions of the tubules, Renal threshold, Tubular maximum, Abnormal constituents of urine, Proteinuria, Reducing sugars, Clearance tests, Creatinine clearance test, Urea clearance test.

APPENDICES I Abbreviations Used in this book ...... 281 II Normal Values (Reference Values) ...... 283 III Recommended Daily Allowance (RDA) of Essential Nutrients ...... 284 IV Composition of Nutrients in Selected Common Food Materials ...... 285 Essay Questions and Short Notes ...... 286

Index ...... 293 ..