Allosteric Regulatory Enzymes
(Sprache: Englisch)
This book covers the most recent developments in the analysis of allosteric enzymes and provides a logical introduction to the limits for enzyme function as dictated by the factors that are limits for life. The book presents a complete description of all...
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This book covers the most recent developments in the analysis of allosteric enzymes and provides a logical introduction to the limits for enzyme function as dictated by the factors that are limits for life. The book presents a complete description of all the mechanisms used for changing enzyme activity. It is extensively illustrated to clarify kinetic and regulatory properties. Eight enzymes are used as model systems after extensive study of their mechanisms. Wherever possible, the human form of the enzyme is used to illustrate the regulatory features.
Klappentext zu „Allosteric Regulatory Enzymes “
All enzymes are remarkable since they have the ability to increase the rate of a chemical reaction, often by more than a billion-fold. Allosteric enzymes are even more amazing because the have the additional ability to change their rate in response to cellular activators or inhibitors. This enables them to control the pathway in which they are the regulatory enzyme. Since the effector molecules represent the current status of the cell for a given metabolic pathway, this results in very responsive and balanced metabolic states, and makes it possible for cells and organisms to be appropriately dynamic, and responsive, in a changing environment. This book provides a logical introduction to the limits for enzyme function as dictated by the factors that are limits for life. This book presents a complete description of all the mechanisms used for changing enzyme acticity. Eight enzymes are used as model systems after extensive study of their mechanisms. Wherever possible, the human form of the enzyme is used to illustrate the regulatory features.
All enzymes are remarkable since they have the ability to increase the rate of a chemical reaction, often by more than a billion-fold. Allosteric enzymes are even more amazing because the have the additional ability to change their rate in response to cellular activators or inhibitors. This enables them to control the pathway in which they are the regulatory enzyme. Since the effector molecules represent the current status of the cell for a given metabolic pathway, this results in very responsive and balanced metabolic states, and makes it possible for cells and organisms to be appropriately dynamic, and responsive, in a changing environment. This book provides a logical introduction to the limits for enzyme function as dictated by the factors that are limits for life. This book presents a complete description of all the mechanisms used for changing enzyme acticity. Eight enzymes are used as model systems after extensive study of their mechanisms. Wherever possible, the human form of the enzyme is used to illustrate the regulatory features.
While authors often emphasize the few enzymes that have the most remarkable catalytic rates, this survery of enzymes has led to the author's appreciation of some important, general conclusions:
1. Most enzymes are not exceptionally fast; they are always good enough for their specific catalytic step.
2. Although enzymes could always be much faster if they changed so as to bind their substrates more weakly, actual enzymes must be able to discriminate in favor of their special substrate, and therefore they have sacrificed speed to obtain better binding. This means that specific control of individual metabolic steps is more important than overall speed.
3. Results for many hundreds of enzymes establish that a lower limit for a normal catalytic activity is 1 s-1. Most enzymes have a catalytic rate between 10 and 300 s-1.
4. Allosteric regulation always results in a chance in the enzymes's affinity for its substrate. Even V-type enzymes (named for their large chance in catalytic velocity) always have a corresponding change in affinity for their substrate.
Thomas Traut has a PhD in molecular biology and has studied enzymes since 1974. As a professor at the University of North Carolina at Chapel Hill, he has focused on enzyme regulation and taught advanced enzymology to graduate students. Important findings from his research helped to define the mechanism of allosteric control for dissociating enzymes.riminate in favor of their special substrate, and therefore they have sacrificed speed to obtain better binding. This means that specific control of individual metabolic steps is more important than overall speed.
3. Results for many hundreds of enzymes establish that a lower limit for a normal catalytic activity is 1 s-1. Most enzymes have a catalytic rate between 10 and 300 s-1.
4. Allosteric regulation always results in a chance in the enzymes's affinity for its s
While authors often emphasize the few enzymes that have the most remarkable catalytic rates, this survery of enzymes has led to the author's appreciation of some important, general conclusions:
1. Most enzymes are not exceptionally fast; they are always good enough for their specific catalytic step.
2. Although enzymes could always be much faster if they changed so as to bind their substrates more weakly, actual enzymes must be able to discriminate in favor of their special substrate, and therefore they have sacrificed speed to obtain better binding. This means that specific control of individual metabolic steps is more important than overall speed.
3. Results for many hundreds of enzymes establish that a lower limit for a normal catalytic activity is 1 s-1. Most enzymes have a catalytic rate between 10 and 300 s-1.
4. Allosteric regulation always results in a chance in the enzymes's affinity for its substrate. Even V-type enzymes (named for their large chance in catalytic velocity) always have a corresponding change in affinity for their substrate.
Thomas Traut has a PhD in molecular biology and has studied enzymes since 1974. As a professor at the University of North Carolina at Chapel Hill, he has focused on enzyme regulation and taught advanced enzymology to graduate students. Important findings from his research helped to define the mechanism of allosteric control for dissociating enzymes.riminate in favor of their special substrate, and therefore they have sacrificed speed to obtain better binding. This means that specific control of individual metabolic steps is more important than overall speed.
3. Results for many hundreds of enzymes establish that a lower limit for a normal catalytic activity is 1 s-1. Most enzymes have a catalytic rate between 10 and 300 s-1.
4. Allosteric regulation always results in a chance in the enzymes's affinity for its s
Inhaltsverzeichnis zu „Allosteric Regulatory Enzymes “
SECTION 1. INTRODUCTION TO ENZYMES 1. INTRODUCTION TO ENZYMES
1.1 INTRODUCTION
1.1.1 Why Are Enzymes Needed?
1.1.2 Allosteric Enzymes
1.2 THE STRUCTURES AND CONFORMATIONS OF PROTEINS
1.2.1 Protein Conformations
1.2.2 Protein Structures
1.2.3 Multi-domain Proteins
1.2.3.1 Evolution of Multi-domain Proteins
1.2.3.2 Interaction Between Domains
1.2.3.3 Alternate Oligomer Structures for the Same Enzyme
1.3 NORMAL VALUES FOR CONCENTRATIONS AND RATES
1.3.1 Concentrations of Enzymes
1.3.2 How Fast Are Enzymes?
1.4 BRIEF HISTORY OF ENZYMES
1.5 USEFUL RESOURCES
1.5.1 Websites
1.5.2 Reference Books
1.5.2.1 General Enzymology
1.5.2.2 Allosteric Enzymes
1.5.2.3 Enzyme Kinetics
1.5.2.4 Ligand Binding and Energetics
1.5.2.5 Enzyme Chemistry and Mechanisms
1.5.2.6 Enzymes in Metabolism
1.5.2.7 History of Enzymology
1.5.2.8 Hemoglobin
2. THE LIMITS FOR LIFE DEFINE THE LIMITS FOR ENZYMES
2.1 NATURAL CONSTRAINTS THAT ARE LIMITING
2.1.1 The Possible Concentration of Enzymes is Most Likely to be Limiting
2.1.2 The Rate for Enzymatic Steps Must Be Faster than Natural, but Undesired and Harmful Reactions
2.1.2.1 Oxygen Radicals
2.1.2.2 Metabolic Acidity
2.1.2.3 Ultraviolet Radiation
2.1.3 DNA Modifyng Enzymes: Accuracy Is More Important Than Speed
2.1.4 Signaling Systems: Why Very Slow Rates Can Be Good
2.1.5 What Is the Meaning of the Many Enzymes for Which Slow Rates Have Been Published?
2.2 PARAMETERS FOR BINDING CONSTANTS
2.2.1 The Importance of Being Good Enough
2.2.2 The Range of Binding Constants
2.3 Enzyme specificity: kcat/Km
2.3.1 A Constant kcat/Km May Permit Appropriate Changes for Enzymes With the Same Enzyme Mechanism
2.3.2 The Specificity Constant May Apply to Only One of the Two Substrates for a Group of Enzymes With the Same Mechanism
2.3.3 The Same Enzyme Can Maintain Constant Specificity While Adapting to Changes
2.3.4 The Limits to kcat/Km
2.2.5 Ribozymes and the RNA World?
3.
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ENZYME KINETICS
3.1 TIME FRAMES FOR MEASURING ENZYME PROPERTIES
3.2 STEADY STATE KINETICS
3.2.1 The Meaning of v and kcat
3.3 The Most Common Graphic Plots
3.3.1 The Michaelis-Menten Plot
3.3.2 The Lineweaver-Burk Plot
3.3.3 The Eadie-Hofstee Plot
3.3.4 The Hill Plot
3.4 Interpreting Binding Constants
3.5 ENERGETICS OF ENZYME REACTIONS
3.5.1 Michaelis-Menten Model
3.5.2 Briggs-Haldane Model
3.5.3 Additional Intermediates Model
4. PROPERTIES AND EVOLUTION OF ALLOSTERIC ENZYMES
4.1 DIFFERENT PROCESSES FOR CONTROLLING THE ACTIVITY OF AN ENZYMATIC REACTION
4.1.1 Modifying the Activity of an Existing Enzyme
4.1.2 Modifying activity by ligand binding
4.1.3 Modifying activity by covalent modification
4.1.4 Modifying activity by altered gene transcription
4.1.5 Modifying activity by proteolysis
4.2 EVOLVING ALLOSTERIC ENZYMES
4.2.1 Allostric Regulation by Stabilizing the Appropriate Species in an Ensemble
4.2.2 Evolution of Allosteric Enzymes
4.3 URACIL PHOPHORIBOSYLTRANSFERASE: DIFFERENT REGULATORY STRATEGIES FOR THE SAME ENZYME
5. KINETICS OF ALLOSTERIC ENZYMES
5.1 KINETICS FOR COOPERATIVE K-TYPE ENZYMES
5.1.1 The MWC Model for Positive Cooperativity
5.1.2 The Influence of the Key Parameters on the Extent of Positive Cooperativity
5.1.2.1 Homotropic Effects
5.1.2.2 Heterotropic Effects
5.2 RNA RIBOSWITCHES ALSO SHOW ALLOSTERIC BINDING
5.3 NEGATIVE COOPERATIVITY
5.3.1 Different Mechanisms Produce Negative Cooperativity
5.3.1.1 Half-of-the-sites Activity
5.3.2 Improper Enzyme Samples May Produce Erroneous Negative Cooperativity
5.3.3 Morpheeins Display Negative Coperativity
5.3.4 Comparison of the MWC and KNF Models
5.4 Conformational Change or Induced Fit?
5.5 ALLOSTERIC SENSITIVITY AND MOLECULAR SWITCHES
5.5.1 Enzyme Cascades and the Extent of Positive Cooperativity In Vitro
5.5.2 Enzyme Cascades and the Extent of Positive Cooperativity In Vivo
SECTION 2. K-TYPE ENZYMES
6. HEMOGLOBIN
6.1. OVERVIEW OF HEMOGLOBINS
6.1.1. The Late Appearance of Oxygen in the Evolution of Life
6.1.2. The Diversity of Globins
6.1.3. Diversity of Globin Structures and Kinetics
6.1.4. Hemoglobin and Its History in Understanding Cooperative Binding
6.1.5. Types of Globins and Their Normal Functions
6.1.6. Converting Binding Constants to Molar Units and for 37 °C and pH7.4
6.2. COOPERATIVITY
6.2.1. Structural Mechanism for Cooperativity
6.2.2. Regulatory Effectors
6.2.2.1. Bohr Effect
6.2.2.2. Temperature
6.2.3. Special Regulatory Effectors
6.2.4. Fetal Hemoglobin
6.3. COOPERATIVITY MEASURED BY DIFFERENT MODELS
6.3.1. Oxygen Binding Without Cooperativity
6.4. HEMOGLOBIN IS ALSO AN ENZYME!
6.4.1. Summary of Hemoglobin Functions
CHAPTER 7. PHOSPHORYLASE
7.1. OVERVIEW OF GLYCOGEN PHOSPHORYLASE
7.1.1. Assay of Glycogen Phosphorylase
7.2. REGULATION OF GLYCOGEN PHOSPHORYLASE
7.2.1. Two Different Activating Mechanisms for Two Different Physiological Needs
7.2.2. Ligands Binding at Two Different Sites on One Subunit
7.2.3. Activation by AMP and IMP
7.2.4. Activation by Other Metabolic Effectors
7.2.5. Activation by Phosphorylation
7.2.6. Summary of Effector Binding
7.3. EVOLUTION OF GLYCOGEN PHOSPHORYLASES
7.3.1. Isozymes of Glycogen Phosphorylase
CHAPTER 8. PHOSPHOFRUCTOKINASE
8.1. The Diversity of Phosphofructokinases
8.1.1. Summary of Phosphofructokinases
8.1.2. Properties and Emergence of Phosphofructokinases
8.1.3. PPi-PFKs
8.2. REGULATION OF PHOSPHOFRUCTOKINASE
8.2.1. Regulation of the Phosphofructokinase in E. coli
8.2.2. Structure of the Bacterial Phosphofructokinase i
8.2.3. Mutation to Reverse Regulation of Bacterial Phosphofructokinase
8.2.4. Regulation of the Mammalian Phosphofructokinase
8.2.5. How Many Binding Sites for ATP?
8.3. Key Regulators of Phosphofructokinase
8.3.1. Effectors for the Bacterial Phosphofructokinase
8.3.2. Effectors for the Mammalian Phosphofructokinase
8.3.3. Effectors of the Yeast Phosphofructokinase
8.3.4. Regulation by Phosphorylation
8.4. ISOZYMES
8.4.1. Binding of Fructose-2,6-P2 by Mammalian Isozymes
8.5. DEFINING A MODEL FOR COOPERATIVITY
8.5.1. Fluorescence Changes with Different Ligands
CHAPTER 9. RIBONUCLEOTIDE REDUCTASE
9.1 THE DIVERSITY OF RIBONUCLEOTIDE REDUCTASES
9.1.1 Evolution of Ribonucleotide Reductases
9.2 BINDING OF NUCLEOTIDES TO RIBONUCLEOTIDE REDUCTASE
9.2.1 Binding of dATP
9.2.2 Binding of ATP
9.2.3 Binding of dTTP and dGTP
9.2.4 Competition Between Regulatory Nucleotides
9.3 REGULATION OF RIBONUCLEOTIDE REDUCTASE FROM E. COLI
9.3.1 Regulation by ATP and dATP
9.3.2 dTTP at the S Site Promotes the Reduction of CDP
9.3.3 dTTP at the A Site Inhibits the Reduction of CDP
9.3.4 ATP Activates by Binding at the S Site
9.3.5 Binding at the A Site Determines the Overall Conformation and Activity
9.4 REGULATION OF RIBONUCLEOTIDE REDUCTASE FROM CALF
9.5 REGULATION BY ALTERNATE, NOVEL R2 SUBUNITS
9.6 A GENERAL MODEL
CHAPTER 10. HEXOKINASE
10.1 INTRODUCTION
10.1.1 Functions of Different Hexokinases
10.1.2 Continuing Need for a Hexokinase IV
10.2 FunctionS of the Duplicated Domain
10.2.1 Product Inhibition at the Catalytic Site
10.2.2 The N-Terminal Half Has Membrane Binding Sites
10.2.3 Negative Cooperativity Due to Separate Binding Sites Within a Monomer
10.2.4 Negative Cooperativity Due to a Mixture of Isozymes
10.3 Positive Cooperativity in a Monomeric Enzyme
10.3.1 Models to Explain Cooperativity in a Monomeric Enzyme
10.3.2 The Slow Transition Model
10.3.3 Positive Cooperativity is a Kinetic Effect
10.3.3.1. A Burst or a Lag Defines the Time for Conformational Change
10.3.3.2 Ligand Binding Itself Has No Cooperativity
10.3.3.3 Glucose Activates Phosphorylation of Fructose
10.3.4 The Mnemonic Model
10.4 regulators of Glucokinase
10.4.1 Small Molecule or Metabolite Activators
10.4.2 Glucokinase Regulatory Protein
10.4.3 Inhibition of Hexokinase IV by Lipids
10.4.4 Need for Multiple Hexokinases
10.5 EVOLUTION OF HEXOKINASES
10.5.1 Expansion of a Basic Precursor
SECTION 3. V-TYPE ENZYMES CHAPTER
11. INTRODUCTION TO V-TYPE ENZYMES
11.1 OVERVIEW OF V-TYPE ENZYMES
11.2 ENZYMES WITH A MODEST CHANGE IN VMAX AND KM
11.2.1 Mercaptopyruvate Sulfurtransferase
11.2.2 Uracil Phospphoribosyltransfrase
11.2.3 Phosphoglycerate Dehydrogense
11.3 ENZYMES WITH LARGE CHANGES IN VMAX AND KM
11.3.1 AMP Nucleosidase
11.3.2 Regulatory Switches
11.3.3 Exceptions
CHAPTER 12. G-PROTEINS
12.1 OVERVIEW OF G-PROTEINS
12.1.1 p21ras
12.1.2 Mechanism of p21ras
12.2 GEFS LOWER THE AFFINITY OF P21 FOR GUANINE NUCLEOTIDES
12.2.1 Changes in Affinity for Guanine Nucleotides Produced by GEF
12.2.2 Specificity of the Guanine Nucleotide Binding Site
12.2.3 Performing Binding Measurements for Tight Binding Ligands
12.3 ONCOGENIC MUTANTS OF P21
CHAPTER 13. PROTEIN KINASES
13.1 OVERVIEW OF PROTEIN KINASES
13.2 MAP KINASES
13.2.1 p38 MAP Kinases
13.2.1.1 Inhibition of p38 at a Novel Allosteric Site
13.2.2 p42 MAP Kinase
13.2.3 AMP-activated ProteinKinase
13.2.4 cAMP-activated ProteinKinase
13.2.4.1 Both cAMP Sites Are Not Required for Activation
13.2.3.2 The Two cAMP Sites Have Different Dissociation Rates
13.2.3.3 ATP Alters the Affinity for cAMP
REFERENCES INDEX
3.1 TIME FRAMES FOR MEASURING ENZYME PROPERTIES
3.2 STEADY STATE KINETICS
3.2.1 The Meaning of v and kcat
3.3 The Most Common Graphic Plots
3.3.1 The Michaelis-Menten Plot
3.3.2 The Lineweaver-Burk Plot
3.3.3 The Eadie-Hofstee Plot
3.3.4 The Hill Plot
3.4 Interpreting Binding Constants
3.5 ENERGETICS OF ENZYME REACTIONS
3.5.1 Michaelis-Menten Model
3.5.2 Briggs-Haldane Model
3.5.3 Additional Intermediates Model
4. PROPERTIES AND EVOLUTION OF ALLOSTERIC ENZYMES
4.1 DIFFERENT PROCESSES FOR CONTROLLING THE ACTIVITY OF AN ENZYMATIC REACTION
4.1.1 Modifying the Activity of an Existing Enzyme
4.1.2 Modifying activity by ligand binding
4.1.3 Modifying activity by covalent modification
4.1.4 Modifying activity by altered gene transcription
4.1.5 Modifying activity by proteolysis
4.2 EVOLVING ALLOSTERIC ENZYMES
4.2.1 Allostric Regulation by Stabilizing the Appropriate Species in an Ensemble
4.2.2 Evolution of Allosteric Enzymes
4.3 URACIL PHOPHORIBOSYLTRANSFERASE: DIFFERENT REGULATORY STRATEGIES FOR THE SAME ENZYME
5. KINETICS OF ALLOSTERIC ENZYMES
5.1 KINETICS FOR COOPERATIVE K-TYPE ENZYMES
5.1.1 The MWC Model for Positive Cooperativity
5.1.2 The Influence of the Key Parameters on the Extent of Positive Cooperativity
5.1.2.1 Homotropic Effects
5.1.2.2 Heterotropic Effects
5.2 RNA RIBOSWITCHES ALSO SHOW ALLOSTERIC BINDING
5.3 NEGATIVE COOPERATIVITY
5.3.1 Different Mechanisms Produce Negative Cooperativity
5.3.1.1 Half-of-the-sites Activity
5.3.2 Improper Enzyme Samples May Produce Erroneous Negative Cooperativity
5.3.3 Morpheeins Display Negative Coperativity
5.3.4 Comparison of the MWC and KNF Models
5.4 Conformational Change or Induced Fit?
5.5 ALLOSTERIC SENSITIVITY AND MOLECULAR SWITCHES
5.5.1 Enzyme Cascades and the Extent of Positive Cooperativity In Vitro
5.5.2 Enzyme Cascades and the Extent of Positive Cooperativity In Vivo
SECTION 2. K-TYPE ENZYMES
6. HEMOGLOBIN
6.1. OVERVIEW OF HEMOGLOBINS
6.1.1. The Late Appearance of Oxygen in the Evolution of Life
6.1.2. The Diversity of Globins
6.1.3. Diversity of Globin Structures and Kinetics
6.1.4. Hemoglobin and Its History in Understanding Cooperative Binding
6.1.5. Types of Globins and Their Normal Functions
6.1.6. Converting Binding Constants to Molar Units and for 37 °C and pH7.4
6.2. COOPERATIVITY
6.2.1. Structural Mechanism for Cooperativity
6.2.2. Regulatory Effectors
6.2.2.1. Bohr Effect
6.2.2.2. Temperature
6.2.3. Special Regulatory Effectors
6.2.4. Fetal Hemoglobin
6.3. COOPERATIVITY MEASURED BY DIFFERENT MODELS
6.3.1. Oxygen Binding Without Cooperativity
6.4. HEMOGLOBIN IS ALSO AN ENZYME!
6.4.1. Summary of Hemoglobin Functions
CHAPTER 7. PHOSPHORYLASE
7.1. OVERVIEW OF GLYCOGEN PHOSPHORYLASE
7.1.1. Assay of Glycogen Phosphorylase
7.2. REGULATION OF GLYCOGEN PHOSPHORYLASE
7.2.1. Two Different Activating Mechanisms for Two Different Physiological Needs
7.2.2. Ligands Binding at Two Different Sites on One Subunit
7.2.3. Activation by AMP and IMP
7.2.4. Activation by Other Metabolic Effectors
7.2.5. Activation by Phosphorylation
7.2.6. Summary of Effector Binding
7.3. EVOLUTION OF GLYCOGEN PHOSPHORYLASES
7.3.1. Isozymes of Glycogen Phosphorylase
CHAPTER 8. PHOSPHOFRUCTOKINASE
8.1. The Diversity of Phosphofructokinases
8.1.1. Summary of Phosphofructokinases
8.1.2. Properties and Emergence of Phosphofructokinases
8.1.3. PPi-PFKs
8.2. REGULATION OF PHOSPHOFRUCTOKINASE
8.2.1. Regulation of the Phosphofructokinase in E. coli
8.2.2. Structure of the Bacterial Phosphofructokinase i
8.2.3. Mutation to Reverse Regulation of Bacterial Phosphofructokinase
8.2.4. Regulation of the Mammalian Phosphofructokinase
8.2.5. How Many Binding Sites for ATP?
8.3. Key Regulators of Phosphofructokinase
8.3.1. Effectors for the Bacterial Phosphofructokinase
8.3.2. Effectors for the Mammalian Phosphofructokinase
8.3.3. Effectors of the Yeast Phosphofructokinase
8.3.4. Regulation by Phosphorylation
8.4. ISOZYMES
8.4.1. Binding of Fructose-2,6-P2 by Mammalian Isozymes
8.5. DEFINING A MODEL FOR COOPERATIVITY
8.5.1. Fluorescence Changes with Different Ligands
CHAPTER 9. RIBONUCLEOTIDE REDUCTASE
9.1 THE DIVERSITY OF RIBONUCLEOTIDE REDUCTASES
9.1.1 Evolution of Ribonucleotide Reductases
9.2 BINDING OF NUCLEOTIDES TO RIBONUCLEOTIDE REDUCTASE
9.2.1 Binding of dATP
9.2.2 Binding of ATP
9.2.3 Binding of dTTP and dGTP
9.2.4 Competition Between Regulatory Nucleotides
9.3 REGULATION OF RIBONUCLEOTIDE REDUCTASE FROM E. COLI
9.3.1 Regulation by ATP and dATP
9.3.2 dTTP at the S Site Promotes the Reduction of CDP
9.3.3 dTTP at the A Site Inhibits the Reduction of CDP
9.3.4 ATP Activates by Binding at the S Site
9.3.5 Binding at the A Site Determines the Overall Conformation and Activity
9.4 REGULATION OF RIBONUCLEOTIDE REDUCTASE FROM CALF
9.5 REGULATION BY ALTERNATE, NOVEL R2 SUBUNITS
9.6 A GENERAL MODEL
CHAPTER 10. HEXOKINASE
10.1 INTRODUCTION
10.1.1 Functions of Different Hexokinases
10.1.2 Continuing Need for a Hexokinase IV
10.2 FunctionS of the Duplicated Domain
10.2.1 Product Inhibition at the Catalytic Site
10.2.2 The N-Terminal Half Has Membrane Binding Sites
10.2.3 Negative Cooperativity Due to Separate Binding Sites Within a Monomer
10.2.4 Negative Cooperativity Due to a Mixture of Isozymes
10.3 Positive Cooperativity in a Monomeric Enzyme
10.3.1 Models to Explain Cooperativity in a Monomeric Enzyme
10.3.2 The Slow Transition Model
10.3.3 Positive Cooperativity is a Kinetic Effect
10.3.3.1. A Burst or a Lag Defines the Time for Conformational Change
10.3.3.2 Ligand Binding Itself Has No Cooperativity
10.3.3.3 Glucose Activates Phosphorylation of Fructose
10.3.4 The Mnemonic Model
10.4 regulators of Glucokinase
10.4.1 Small Molecule or Metabolite Activators
10.4.2 Glucokinase Regulatory Protein
10.4.3 Inhibition of Hexokinase IV by Lipids
10.4.4 Need for Multiple Hexokinases
10.5 EVOLUTION OF HEXOKINASES
10.5.1 Expansion of a Basic Precursor
SECTION 3. V-TYPE ENZYMES CHAPTER
11. INTRODUCTION TO V-TYPE ENZYMES
11.1 OVERVIEW OF V-TYPE ENZYMES
11.2 ENZYMES WITH A MODEST CHANGE IN VMAX AND KM
11.2.1 Mercaptopyruvate Sulfurtransferase
11.2.2 Uracil Phospphoribosyltransfrase
11.2.3 Phosphoglycerate Dehydrogense
11.3 ENZYMES WITH LARGE CHANGES IN VMAX AND KM
11.3.1 AMP Nucleosidase
11.3.2 Regulatory Switches
11.3.3 Exceptions
CHAPTER 12. G-PROTEINS
12.1 OVERVIEW OF G-PROTEINS
12.1.1 p21ras
12.1.2 Mechanism of p21ras
12.2 GEFS LOWER THE AFFINITY OF P21 FOR GUANINE NUCLEOTIDES
12.2.1 Changes in Affinity for Guanine Nucleotides Produced by GEF
12.2.2 Specificity of the Guanine Nucleotide Binding Site
12.2.3 Performing Binding Measurements for Tight Binding Ligands
12.3 ONCOGENIC MUTANTS OF P21
CHAPTER 13. PROTEIN KINASES
13.1 OVERVIEW OF PROTEIN KINASES
13.2 MAP KINASES
13.2.1 p38 MAP Kinases
13.2.1.1 Inhibition of p38 at a Novel Allosteric Site
13.2.2 p42 MAP Kinase
13.2.3 AMP-activated ProteinKinase
13.2.4 cAMP-activated ProteinKinase
13.2.4.1 Both cAMP Sites Are Not Required for Activation
13.2.3.2 The Two cAMP Sites Have Different Dissociation Rates
13.2.3.3 ATP Alters the Affinity for cAMP
REFERENCES INDEX
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Autoren-Porträt von Thomas W. Traut
Thomas Traut has a PhD in molecular biology and has studied enzymes since 1974. As a professor at the University of North Carolina at Chapel Hill, he has focused on enzyme regulation and taught advanced enzymology to graduate students. Important findings from his research helped to define the mechanism of allosteric control for dissociating enzymes.
Bibliographische Angaben
- Autor: Thomas W. Traut
- 2010, XIV, 250 Seiten, Maße: 15,5 x 23,5 cm, Kartoniert (TB), Englisch
- Verlag: Springer, Berlin
- ISBN-10: 1441944532
- ISBN-13: 9781441944535
Sprache:
Englisch
Pressezitat
From the reviews: "This holistic introduction to enzymes in general covers the history of their discovery and the different mechanisms of action before going into an in-depth presentation of particular allosteric enzymes and enzyme families. ... This book will be of great help to graduate students and postdoctoral fellows interested in understanding the theory behind the action of allosteric enzymes. ... an excellent book of enzymology focusing on the mechanisms employed by allosteric enzymes and their metabolic regulation." (Helen Anni, Doody's Review Service, October, 2008)
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