Evaluation of Enzyme Inhibitors in Drug Discovery: A Guide for Medicinal Chemists and Pharmacologists, Second Edition

**Offers essential guidance for discovering and optimizing novel drug therapies** Using detailed examples, __Evaluation of Enzyme Inhibitors in Drug Discovery__ equips researchers with the tools needed to apply the science of enzymology and biochemistry to the discovery, optimization, and preclinical development of drugs that work by inhibiting specific enzyme targets. Readers will applaud this book for its clear and practical presentations, including its expert advice on best practices to follow and pitfalls to avoid. This __Second Edition__ brings the book thoroughly up to date with the latest research findings and practices. Updates explore additional forms of enzyme inhibition and special treatments for enzymes that act on macromolecular substrates. Readers will also find new discussions detailing the development and application of the concept of __drug-target residence time__. __Evaluation of Enzyme Inhibitors in Drug Discovery__ begins by explaining why enzymes are such important drug targets and then examines enzyme reaction mechanisms. The book covers: * Reversible modes of inhibitor interactions with enzymes * Assay considerations for compound library screening * Lead optimization and structure-activity relationships for reversible inhibitors * Slow binding and tight binding inhibitors * Drug-target residence time * Irreversible enzyme inactivators The book ends with a new chapter exploring the application of quantitative biochemical principles to the pharmacologic evaluation of drug candidates during lead optimization and preclinical development. The __Second Edition__ of __Evaluation of Enzyme Inhibitors in Drug Discovery__ continues to offer a treatment of enzymology applied to drug discovery that is quantitative and mathematically rigorous. At the same time, the clear and simple presentations demystify the complex science of enzymology, making the book accessible to many fields? from pharmacology to medicinal chemistry to biophysics to clinical medicine.Content: Chapter 1 Why Enzymes as Drug Targets? (pages 1–23): Chapter 2 Enzyme Reaction Mechanisms (pages 25–55): Chapter 3 Reversible Modes of Inhibitor Interactions with Enzymes (pages 57–121): Chapter 4 Assay Considerations for Compound Library Screening (pages 123–168): Chapter 5 Lead Optimization and Structure–Activity Relationships for Reversible Inhibitors (pages 169–201): Chapter 6 Slow Binding Inhibitors (pages 203–244): Chapter 7 Tight Binding Inhibition (pages 245–285): Chapter 8 Drug–Target Residence Time (pages 287–344): Chapter 9 Irreversible Enzyme Inactivators (pages 345–382): Chapter 10 Quantitative Biochemistry in the Pharmacological Evaluation of Drugs (pages 383–469): There Has Been Explosive Growth In The Hunt For New Pharmaceutically Agents Globally. Traditionally, This Has Been The Purview Of The Pharmaceutical Industry, But Today, This Effort Crosses Academic, Government, And Industry Laboratories Across The World. Enzymes Remain The Most Valued And Common Of Drug Targets; Hence, A Detailed Understanding Of Their Interactions With Inhibitors Is Critical To Successful Drug Discovery. This Book Provides A Practical, Readable, And Comprehensive Treatment Of These Topics That Allows Scientists To Master The Art Of Applied Enzymology For Drug Discovery. The Book Addresses The Opportunities For Inhibitor Interactions With Enzyme Targets Arising From Consideration Of The Catalytic Reaction Mechanism; Discusses How Inhibitors Are Properly Evaluated For Potency, Selectivity, And Mode Of Action, Covers The Potential Advantages And Liabilities Of Specific Inhibition Modalities With Respect To Efficacy In Vivo, And Provides Valuable Biochemical Insights To Help Medicinal Chemists And Pharmacologists Most Effectively Pursue Lead Optimization. It Includes Two New Chapters, One On The Pioneering Idea Of Drug-target Residence Time Fostered By Dr. Copeland, And The Second On Quantitative Biochemistry. Five New Appendices Are Added--provided By Publisher. Robert A. Copeland. Machine Generated Contents Note: Foreword. Preface. Acknowledgments. 1. Why Enzymes As Drug Targets?1.1 Enzymes Are Essentials For Life. 1.2 Enzyme Structure And Catalysis. 1.3 Permutations Of Enzyme Structure During Catalysis. 1.4 Other Reasons For Studying Enzymes. 1.5 Summary. References. 2. Enzyme Reaction Mechanisms. 2.1 Initial Binding Of Substrate. 2.2 Noncovalent Forces In Reversible Ligand Binding To Enzymes. 2.2.1 Electrostatic Forces. 2.2.2 Hydrogen Bonds. 2.2.3 Hydrophobic Forces. 2.2.4 Van Der Waals Forces. 2.3 Transformations Of The Bond Substrate. 2.3.1 Strategies For Transition State Stabilization. 2.3.2 Enzyme Active Sites Are Most Complementary To The Transition State Structure. 2.4 Steady State Analysis Of Enzyme Kinetics. 2.4.1 Factors Affecting The Steady State Kinetic Constants. 2.5 Graphical Determination Of Kcat And Km2.6 Reactions Involving Multiple Substates. 2.6.1 Bisubstrate Reaction Mechanisms. 2.7 Summary. References. 3.^ Reversible Modes Of Inhibitor Interactions With Enzymes. 3.1 Enzyme-inhibitor Binding Equilibria. 3.2 Competitive Inhibition. 3.3 Noncompetitive Inhibition. 3.3.1 Mutual Exclusively Studies. 3.4 Uncompetitive Inhibition. 3.5 Inhibition Modality In Bisubstrate Reactions. 3.6 Value Of Knowing Inhibitor Modality. 3.6.1 Quantitative Comparisons Of Inhibitor Affinity. 3.6.2 Relating Ki To Binding Energy. 3.6.3 Defining Target Selectivity By Ki Values. 3.6.4 Potential Advantages And Disadvantages Of Different Inhibition Modalities In Vivo. 3.6.5 Knowing Inhibition Modality Is Important For Structure-based Lead Organization. 3.7 Summary. References. 4. Assay Considerations For Compound Library Screening. 4.1 Defining Inhibition Signal Robustness, And Hit Criteria. 4.2 Measuring Initial Velocity. 4.2.1 End-point And Kinetic Readouts. 4.2.2 Effects Of Enzyme Concentration. 4.3 Balanced Assay Conditions. 4.3.1 Balancing Conditions For Multisubstrate Reactions. 4.4 Order Of Reagent Addition.^ 4.5 Use Of Natural Substrates And Enzymes. 4.6 Coupled Enzyme Assays. 4.7 Hit Validation And Progression. 4.8 Summary. References. 5. Lead Optimization And Structure-activity Relationships For Reversible Inhibitors. 5.1 Concentration-response Plots And Ic50 Determination. 5.1.1 The Hill Coefficient. 5.1.2 Graphing And Reporting Concentration-response Data. 5.2 Testing For Reversibility. 5.3 Determining Reversible Inhibition Modality And Dissociation Constant. 5.4 Comparing Relative Affinity. 5.4.1 Compound Selectivity. 5.5 Associating Cellular Effects With Target Enzyme Inhibition. 5.5.1 Cellular Phenotype Should Be Consistent With Genetic Knockout Or Knockdown Of The Target Enzyme. 5.5.2 Cellular Activity Should Require A Certain Affinity For The Target Enzyme. 5.5.3 Buildup Of Substrate And/or Diminution Of Product For The Target Enzyme Should Be Observed In Cells.^ 5.5.4 Cellular Phenotype Should Be Reversed By Cell-permeable Product Or Downstream Metabolites Of The Target Enzyme Activity. 5.5.5 Mutation Of The Target Enzyme Should Lead To Resistance Or Hypersensitivity To Inhibitors. 5.6 Summary. References. 6. Slow Binding Inhibitors. 6.1 Determining Kobs: The Rate Constant For Onset Of Inhibition. 6.2 Mechanisms Of Slow Binding Inhibition. 6.3 Determination Of Mechanism And Assessment Of True Affinity. 6.3.1 Potential Clinical Advantages Of Slow Off-rate Inhibitors. 6.4 Determining Inhibition Modality For Slow Binding Inhibitors. 6.5 Sar For Slow Binding Inhibitors. 6.6 Some Examples Of Pharmacologically Interesting Slow Binding Inhibitors. 6.6.1 Examples Of Scheme B: Inhibitors Of Zinc Peptidases And Proteases. 6.6.2 Example Of Scheme C: Inhibition Of Dihydrofolate Reductase By Methotresate. 6.6.3 Example Of Scheme C: Inhibition Of Calcineurin By Fkbp-inhibitor Complexes. 6.6.4 Example Of Scheme C When Ki*