lecnote fm Med Biochem - Carter Center

1 LECTURE NOTES For Health Science Students Medical Biochemistry Solomon Adugna, Lakshmi Ahuja Mekonnen Alemu, Tsehayneh Kelemu, Henok Tekola, Belayhun Kibret, Solomon Genet Gondar University, Jimma University, Debub University In collaboration with the Ethiopia Public Health Training Initiative, The Carter Center , the Ethiopia Ministry of Health, and the Ethiopia Ministry of Education 2004 Funded under USAID Cooperative Agreement No. 663-A-00-00-0358-00. Produced in collaboration with the Ethiopia Public Health Training Initiative, The Carter Center , the Ethiopia Ministry of Health, and the Ethiopia Ministry of Education.

2 Important Guidelines for Printing and Photocopying Limited permission is granted free of charge to print or photocopy all pages of this publication for educational, not-for-profit use by health care workers, students or faculty. All copies must retain all author credits and copyright notices included in the original document. Under no circumstances is it permissible to sell or distribute on a commercial basis, or to claim authorship of, copies of material reproduced from this publication. 2004 by Solomon Adugna, Lakshmi Ahuja Mekonnen Alemu, Tsehayneh Kelemu, Henok Tekola, Belayhun Kibret, Solomon Genet All rights reserved.

3 Except as expressly provided above, no part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage and retrieval system, without written permission of the author or authors. This material is intended for educational use only by practicing health care workers or students and faculty in a health care field. iTable of Contents Table of Contents .. i Acknowledgement .. v Introduction .. vi Solomon Adugna and Lakshmi Ahuja Unit One: Enzymes.

4 1 Henok Tekola Principles and classifications of Enzymes .. 5 Mechanism action of Enzymes .. 7 Enzyme Inhibition .. 13 Regulation of Enzyme activity .. 18 Enzymes in clinical diagnosis .. 19 Unit Two: Carbohydrate metabolism .. 23 Belayhun Kibret Chemistry of Carbohydrates .. 23 Functions of Carbohydrates .. 31 Digestion and absorption of Carbohydrates .. 33 Glycolysis .. 35 Glycogen metabolism .. 42 Glycogen storage diseases .. 45 Pentose phosphate pathway.

5 46 The Cori - cycle .. 48 Gluconeogenesis .. 49 Unit Three: Integrative metabolism Bioenergetics .. 54 Tsehayneh Kelemu Introduction .. 54 Structural basis of high energy phosphate .. 55 Formation and utilization of ATP .. 56 Catabolism of fuel molecules .. 56 Concept of Free energy .. 58 Oxidation-reduction reactions .. 58 Aerobic energy generation .. 61 Kreb s cycle .. 63 Function and regulation of kreb s cycle .. 70 iiElectron transport system and oxidative Phosphorylation .. 71 Respiratory control.

6 77 Uncouplers .. 77 Respiratory poisons .. 78 Unit Four: Lipid metabolism .. 80 Solomon Genet Classification of Lipids .. 80 Types of Lipids .. 80 Digestion and absorption of Lipids .. 86 metabolism of Fatty acids and Triacyl Glycerols .. 88 -Oxidation of Fatty acids .. 90 metabolism of Ketone bodies .. 93 Biosynthesis of Fatty acids and triacyl glycerols .. 97 Cholesterol metabolism .. 99 Atherosclerosis .. 101 Hypercholesterolemic drugs .. 101 Lipid storage diseases.

7 102 Fatty Liver .. 102 Lipoproteins .. 102 Chemical compositions of Membranes .. 104 Unit Five: Amino acids and Proteins .. 105 Solomon Adugna Classification of amino acids .. 106 Properties of amino acids .. 115 Peptides .. 119 Glutathione synthesis .. 121 Proteins .. 124 Classifications of proteins .. 124 Levels of organization of proteins .. 126 Denaturation of proteins .. 131 Hemoglobin and Myoglobin .. 135 Sickle cell Hemoglobin .. 136 Sickle cell disease, Sickle cell trait .. 136 Digestion and absorption of proteins.

8 137 Amino acid catabolism .. 141 Nitrogen balance, excretion and the urea cycle .. 144 iiiDefects in the urea cycle .. 150 The Glucose - Alanine cycle .. 151 Inborn errors of amino acid metabolism .. 152 Amino acid derived nitrogenous compounds .. 154 Clinical problems .. 159 Unit Six: Vitamins and Coenzymes .. 161 Solomon Adugna Water soluble vitamins .. 161 Chemistry, sources, function and deficiency of: Thamine .. 161 Riboflavin .. 163 Niacin .. 164 Pyridoxine .. 165 Biotin .. 166 Cobalamin .. 167 Folic acid.

9 169 Panthothenic acid .. 170 Ascorbic acid .. 171 Fat soluble vitamins .. 172 Chemistry, Sources, function, deficiency and Hypervitaminosis of: Vitamin A .. 173 Vitamin D .. 177 Vitamin E .. 179 Vitamin K .. 181 Unit Seven: Miniral metabolism .. 183 Lakshmi Ahuja Mineral .. 183 Sodium and potassium .. 183 Calcium and Phosphate .. 184 Trace elements .. 185 Iron .. 185 Copper .. 187 Magnesium .. 188 Flourine .. 188 Iodine .. 189 Zinc .. 189 ivSelenium .. 191 Unit Eight: Hormones.

10 193 Lakshmi Ahuja Definition and classification .. 194 Biosynthesis, storage, transport .. 196 Mechanism of action of steroid hormones .. 197 Mechanism of action of protein hormones .. 198 Receptors and diseases .. 202 Second messengers .. 203 Insulin synthesis, secretion and metabolic role .. 205 Diabetes mellitus .. 209 Symptoms and complications of DM.. 210 Glucagon .. 211 Clinical aspects .. 212 Thyroxin .. 213 Synthesis and metabolism .. 213 Hypo and Hyper Thyroidism .. 214 Goiter .. 215 Catecholamines.