Enzymes

PrefaceI. IntroductionII. Enzyme Techniques Measurement of Velocity Classes of Methods Some Practical Points The General Handling of Enzymes The Study of an Enzyme The Specific and Molecular Activities Enzyme Affinities Methods of Quantitatively Following Enzyme Reactions (a) Spectrophotometric Methods (b) Manometric Methods (c) The Thunberg Method (d) Electrode Methods (e) Polarimetric Methods (f) Chromatographic Methods (g) Chemical EstimationsIII. Enzyme Isolation Importance of Enzyme Purification Methods of Purification (a) Test (b) General Procedure (c) Source of Enzyme (d) Extraction Fractionation Methods (a) Fractional Precipitation by Change of pH (b) Fractional Denaturation by Heating (c) Fractional Precipitation with Organic Solvents (d) Fractional Precipitation by Salts (e) Fractional Adsorption (f) Column Chromatography (g) Crystallization (h) Sequence of Fractionation Methods (i) Other Methods Criteria of Purity of Enzymes Pitfalls in Working with Pure EnzymesIV. Enzyme Kinetics The Importance of Enzyme Kinetics Factors Influencing Enzyme Reaction Velocity (A) Effect of Enzyme Concentration (B) Effect of Substrate Concentration (c) Effect of pH (D) Effect of TemperatureV. Enzyme Classification Enzyme Commission's Numbering System Rules for Systematic and Trivial Nomenclatures (i) General Rules (ii) Rules for Particular Classes of Enzymes Enzyme Reactions 1. Oxidoreductases 2. Transferases 3. Hydrolases 4. Lyases 5. Isomerases 6. LigasesVI. Enzyme Specificity The Investigation of Enzyme Specificity General Observations on Specificity Stereospecificity of Enzymes Illustrative Examples of Enzyme Specificity Dehydrogenases Glucose Oxidase Methyltransferases Transketolase and Transaldolase Glycosyltransferases Phosphotransferases Esterases Phosphatases Glycosidases Peptidases Lyases Aldose Mutarotase Enzymes with Substrates Containing Hydrocarbon Chains General ConclusionsVII. Enzyme Mechanisms Mechanism of Hydrogen-Transfer Reactions Alcohol Dehydrogenase Glyceraldehydephosphate Dehydrogenase Lipoamide Dehydrogenase Mechanism of Transferring (or Hydrolysing) Enzymes (a) Identification of the Bond Affected (b) Isotope Exchange Methods (c) The Optical Inversion Method (d) Inferences from Competition and Other Effects (e) Identification of Intermediate Complexes Mechanism of Lyases Fumarate Hydratase Aspartate Ammonia-Lyase Mechanism of Isomerases Epimerases Methylmalonyl-CoA Racemase Cis-trans Isomerases Ketol-Isomerases Δ-Isomerases Methylmalonyl-CoA Mutase Mechanism of Ligases Triple-Transfer Mechanism Ternary Complex Mechanisms Mechanism of Metalloenzymes Metal-Activated Peptidases Zinc-Containing Dehydrogenases Metalloflavoproteins Haemoprotein EnzymesVIII. Enzyme Inhibitors Types of Inhibitors Competitive Inhibitors Non-Competitive Inhibitors 'Mixed-Type' Inhibitors Graphical Presentation of Inhibitor Effects Determination of Inhibitor Constants Other Types of Inhibitors Inhibitors with Very High Affinities Effect of pH on Inhibition Some Important Inhibitors Poisons of Heavy Metals Reagents for Thiol Groups Heavy Metals Irreversible Organophosphorus Inhibitors Inhibitors of Respiration and Phosphorylation Competitive Inhibitors AntienzymesIX. Enzyme Cofactors Specific Coenzymes Hydrogen Carriers Lipoate Glutathione Ascorbate Quinones Cytochromes Cytochrome Oxidase Other Hydrogen Carriers Amino-Group Carriers 2-Oxoglutarate Phosphate Carriers Nucleoside 5'-Diphosphates Mixed Phosphate and Glycosyl Transfers Acyl-Group Carriers Coenzyme A Carriers of One-Carbon Groups Tetrahydrofolate Adenosylhomocysteine Cobamide Coenzymes Prosthetic Groups as Carriers Flavin Groups Pyridoxal Phosphate Thiamine Pyrophosphate Biotin Other Coenzymes Phosphomutase Coenzymes Glutathione as a Specific Coenzyme Relationship Between Coenzymes and Vitamins Significance of 'Nucleotide' Structure in Coenzymes Enzyme Activators Simple Electrolytes Lipophilic Ions Polynucleotide Templates The Distinction Between Prosthetic Group, Coenzyme and SubstrateX. Enzyme Structure Molecular Weight Protein Structure Number of Peptide Chains Aminoacid Composition Aminoacid Sequence Structure and Configuration of the Enzyme Protein The Chemistry of the Active Centre Number of Active Centres Per Molecule Chemical Nature of the Active CentreXI. Enzyme Formation The Biosynthesis of Enzymes Biosynthesis of Proteins Induction and Repression Enzyme Formation from Precursors The Activation of Pepsinogen The Activation of Prorennin The Activation of Trypsinogen The Activation of Chymotrypsinogen The Activation of Procarboxypeptidases Activation of the Pancreatic Complex Other Precursors and their ActivationXII. Enzyme Systems The Biological Importance of Systems of Enzymes Linking of Enzymes Coenzyme-Linked Dehydrogenase Systems Distributive Function of Transferring Enzymes Transit Time Structurally Organized Enzyme Systems Some Properties of Multi-Enzyme Systems Comments on Tables Tables of Enzyme Systems 1. The Glycolysis System 2. The Citric Cycle 3. The Glyoxylate Cycle in Plants and Micro-Organisms 4. Fatty Acid Breakdown and Synthesis 5. The Glucose 6-Phosphate Oxidation System 6. A Hydrogen-Transport System in Plants 7. Phenylalanine Oxidation System 8. The Glyoxalase System 9. The Galactose-Inverting System 10. Methionine Metabolism 11. Glycogen Synthesis 12. Interconversion of Pentoses in Lactobacillus 13. Synthesis of Isoprenoid Compounds 14. Urea Formation in Liver 15. Phosphatide Synthesis 16. Synthesis and Breakdown of NAD and NADP 17. Coenzyme a Synthesis 18. Nucleotide Synthesis 19. Formation of Sucrose in PhotosynthesisXIII. Enzyme Biology Enzymes as the Basis of Life Enzymes and Cell-Structure Intracellular Structures Intracellular Localization of Enzymes Enzyme Localization and Cell Physiology Intraparticulate Organization Comparative Enzyme Biochemistry (a) Comparison of Tissues (b) Comparison of Enzymes The Enzymology of Genetics The Effects of Mutations The Use of Mutations in Elucidating Metabolic Patterns The Origin of EnzymesTable of EnzymesList of Symbols'Atlas' of Crystalline EnzymesReferencesIndex