Detailed Contents 12.5 How Does High-Thro Catalysts Lower the Free Energy ofActivation Allow Global Study of Millions of Genes o for a Reaction 443 Molecules at Once?420 Decreasing AG Increases Reaction Rate 444 High-Throughput Screening 42 13.3 What Equations Define the Kinetic DNA Laser Printing 421 of Enzyme-Catalyzed Reactions?444 The Substrate Binds at the Active Site of an Enzyme 445 2.6 an Enzymatic Reaction 445 stant During etic Deficiencies 423 Assume That Velocity Measurements Are Made Imm iately After Adding S446 onstant,K.Is Defined as 12.7 What Is the New Field of Synthetic Biology?425 Plots of Versus [S]llustrate the Relationships Between DNA as Code 425 V.K-.and Reaction Order 447 iGEM and BioBricks(Registry of Standard iological Parts)425 Ner Defines the Activity of One Ezyme Metabolic The Ratio.KDefines the Catalytic Efficienc) of an Enzyme 449 Genome Prokaryoti nBe eh- a Pr -Woolf Plots Are 428 A5 Synthetic Genomes 430 ongly Influenced by pH 451 SUMMARY 430 A DEEPER LOOK:An Ex e of the Effect of Amino Acid FOUNDATIONAL BIOCHEMISTRY 432 Substitutions onK. and Wild. ype and Mutant PROBLEMS 433 H FURTHER READING 434 Is Complex 453 34 What Can Be lear med from the Inhibition of Enzyme Activity?453 PART II PROTEIN DYNAMICS Enzymes May Be Inhibited Reversibly or Irreversibly 453 13 Enzymes-Kinetics and Specificity 437 Enzymes Are the Agents of Metabolic Function 438 13.1 What Characteristic Features Define Enzymes?438 The of Competitive ataly 13.5 What rof Enzymes Catalyzing UMAN BIOC EMISTRY.Vi Regulation of Enzyme Activity Ensures That the Rate s Appropriate to Cellua The Conversion of AEB to PEQ Is the Rate- clature Provides a Systematic Wa of Naming Metabolic Reactions439 the Leadin Substate Must Bind First 461 9 Coenzymes and Cofactors Are Nonprotein Components Essential to Enzyme Activity 440 oa 13.2 oAre One Way to Diagnose Be Def d in a Ma Multisubstrate Reactions Can Also Occur in Cells 465 13.6 How Can E mes Be S Reactant Molecules 442 s Are Reactions Involving Two Hypothesis Was the First Explanatio Detailed Contents xiii 12.5 How Does High-Throughput Technology Allow Global Study of Millions of Genes or Molecules at Once? 420 High-Throughput Screening 421 DNA Laser Printing 421 High-Throughput RNAi Screening of Mammalian Genomes 422 High-Throughput Protein Screening 422 12.6 Is It Possible to Make Directed Changes in the Heredity of an Organism? 422 Human Gene Therapy Can Repair Genetic Deficiencies 423 Viruses as Vectors in Human Gene Therapy 423 Human Biochemistry: The Biochemical Defects in Cystic Fibrosis and ADA2 SCID 424 12.7 What Is the New Field of Synthetic Biology? 425 DNA as Code 425 iGEM and BioBricks (Registry of Standard Biological Parts) 425 Metabolic Engineering 426 Genome Engineering 427 Genome Editing with CRISPR/Cas9 427 CRITICAL DEVELOPMENTS IN BIOCHEMistry: CRISPR/Cas9—Exploiting the Biology of Prokaryotic Adaptive Immunity to Edit Genomes 428 Synthetic Genomes 430 SUMMARY 430 Foundational Biochemistry 432 PROBLEMS 433 Further Reading 434 Part II Protein Dynamics 13 Enzymes—Kinetics and Specificity 437 Enzymes Are the Agents of Metabolic Function 438 13.1 What Characteristic Features Define Enzymes? 438 Catalytic Power Is Defined as the Ratio of the Enzyme￾Catalyzed Rate of a Reaction to the Uncatalyzed Rate 438 Specificity Is the Term Used to Define the Selectivity of Enzymes for Their Substrates 439 Regulation of Enzyme Activity Ensures That the Rate of Metabolic Reactions Is Appropriate to Cellular Requirements 439 Enzyme Nomenclature Provides a Systematic Way of Naming Metabolic Reactions 439 Coenzymes and Cofactors Are Nonprotein Components Essential to Enzyme Activity 440 13.2 Can the Rate of an Enzyme-Catalyzed Reaction Be Defined in a Mathematical Way? 441 Chemical Kinetics Provides a Foundation for Exploring Enzyme Kinetics 441 Bimolecular Reactions Are Reactions Involving Two Reactant Molecules 442 Catalysts Lower the Free Energy of Activation for a Reaction 443 Decreasing DG‡ Increases Reaction Rate 444 13.3 What Equations Define the Kinetics of Enzyme-Catalyzed Reactions? 444 The Substrate Binds at the Active Site of an Enzyme 445 The Michaelis–Menten Equation Is the Fundamental Equation of Enzyme Kinetics 445 Assume That [ES] Remains Constant During an Enzymatic Reaction 445 Assume That Velocity Measurements Are Made Immediately After Adding S 446 The Michaelis Constant, Km , Is Defined as (k21 1 k2)/k1 446 When [S] 5 Km , v 5 Vmax /2 447 Plots of v Versus [S] Illustrate the Relationships Between Vmax , Km , and Reaction Order 447 Turnover Number Defines the Activity of One Enzyme Molecule 448 The Ratio, kcat /Km , Defines the Catalytic Efficiency of an Enzyme 449 Linear Plots Can Be Derived from the Michaelis–Menten Equation 450 Nonlinear Lineweaver–Burk or Hanes–Woolf Plots Are a Property of Regulatory Enzymes 451 Enzymatic Activity Is Strongly Influenced by pH 451 A Deeper Look: An Example of the Effect of Amino Acid Substitutions on Km and kcat: Wild-Type and Mutant Forms of Human Sulfite Oxidase 452 The Response of Enzymatic Activity to Temperature Is Complex 453 13.4 What Can Be Learned from the Inhibition of Enzyme Activity? 453 Enzymes May Be Inhibited Reversibly or Irreversibly 453 Reversible Inhibitors May Bind at the Active Site or at Some Other Site 453 A Deeper Look: The Equations of Competitive Inhibition 455 Enzymes Also Can Be Inhibited in an Irreversible Manner 458 13.5 What Is the Kinetic Behavior of Enzymes Catalyzing Bimolecular Reactions? 459 Human Biochemistry: Viagra—An Unexpected Outcome in a Program of Drug Design 459 The Conversion of AEB to PEQ Is the Rate-Limiting Step in Random, Single-Displacement Reactions 460 In an Ordered, Single-Displacement Reaction, the Leading Substrate Must Bind First 461 Double-Displacement (Ping-Pong) Reactions Proceed Via Formation of a Covalently Modified Enzyme Intermediate 462 Exchange Reactions Are One Way to Diagnose Bisubstrate Mechanisms 464 Multisubstrate Reactions Can Also Occur in Cells 465 13.6 How Can Enzymes Be So Specific? 465 The “Lock and Key” Hypothesis Was the First Explanation for Specificity 465 Copyright 2017 Cengage Learning. 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