A first edition of this book appeared in Russian language in 1983. Since those days the interest in proteolytic enzymes has acquired a new impulse due to advances in genetic engineering techniques, which facilitated structural and func tional studies of the enzymes. Much more data on a crucial role of proteases in biological processes in norm and pathology are available now. Information that appeared in the past 8 years prompted a renewal of the book and furnishing a supplement especially made for the English edition. The book retains the presentation of the previous edition and yet enlarges the scope to cover the methods for site-directed mutagenesis of amide hydrolases, catalyti cally active antibodies, etc. I have tried to preserve the book as a means of reference for the reader. A list of enzymes has been expanded and the biblio graphy up to 1990 enlarged by half as much. I am grateful to the translators T. E. Chernichko, N. 1. Loboda and my co worker Dr. S. L. Alexandrov for their assistance in the preparation ofthis edition and I feel happy that my book is now available for enzymologists abroad.

Inhaltsangabe1 Substrates.- 1.1 General Characteristics.- 1.2 Amide Group.- 1.2.1 Geometry.- 1.2.2 Electron Structure.- 1.2.3 Properties of the Amide Group.- 1.3 Unusual (Nonpeptide) Amide Bonds and Other Bonds of Carboxylic Acid Derivatives.- 1.3.1 ?-Lactams.- 1.3.2 Ester Bond.- 1.4 Derivatives of Amino Acids and Peptides.- 1.4.1 Ionization and Hydrophobicity.- 1.4.2 Conformation.- 1.5 Proteins as Substrates of Proteases.- 1.6 Water.- 1.7 Conclusion.- 2 Enzymes.- 2.1 Classification.- 2.2 Distribution.- 2.3 Characteristics of Certain Types of Amide Hydrolases.- 2.4 Primary Structure.- 2.4.1 Serine Amide Hydrolases.- 2.4.2 Cysteine Amide Hydrolases.- 2.4.3 Aspartic Amide Hydrolases.- 2.4.4 Metal-Containing Amide Hydrolases.- 2.4.5 Nonprotein Components.- 2.5 Spatial Structure.- 2.5.1 Serine Amide Hydrolases.- 2.5.2 Cysteine Amide Hydrolases.- 2.5.3 Aspartic Amide Hydrolases.- 2.5.4 Metal-Containing Amide Hydrolases.- 2.6 Active Sites.- 2.6.1 Serine Amide Hydrolases.- 2.6.2 Cysteine Amide Hydrolases.- 2.6.3 Aspartic Amide Hydrolases.- 2.6.4 Metal-Containing Amide Hydrolases.- 2.6.5 Structural Similarity and Differences in Active Sites of the Enzymes of Various Groups.- 2.6.6 The Structure of Protease Active Sites in Crystals and Solution.- 2.7 Conformational Mobility of Enzymes.- 2.8 Proteolytic Activity of Enzymes Other than Amide Hydrolases. Catalytically Active Antibodies.- 2.9 Conclusion.- 3 Nonenzymatic Hydrolysis. Models.- 3.1 Thermodynamics.- 3.2 Kinetics.- 3.2.1 Influence of Structure.- 3.2.2 Influence of the Medium.- 3.3 Mechanism.- 3.3.1 Nucleophilic Attack.- 3.3.2 Tetrahedral Intermediates.- 3.3.3 Proton Transfer and Product Formation.- 3.4 Catalysis.- 3.4.1 Classification.- 3.4.2 Catalytic Efficiency.- 3.4.3 Catalysis by a Hydroxyl Group.- 3.4.4 Thiol Group.- 3.4.5 Carboxyl Group.- 3.4.6 Catalysis by Metal Ions.- 3.4.7 Imidazole Catalysis.- 3.4.8 Intramolecular and Polyfunctional Catalysis.- 3.4.9 Micellar Catalysis.- 3.4.10 Macromolecular Models of Amide Hydrolases.- 3.5 Conclusion.- 4 Enzyme Hydrolysis. Phenomenology.- 4.1 Enzyme Kinetics.- 4.1.1 Steady-State Kinetics.- 4.1.2 Method for Detecting Kinetic Parameters.- 4.1.3 Meaning and Value of Kinetic Constants.- 4.1.4 Nonproductive Binding.- 4.1.5 Detection of Individual Kinetic Constants.- 4.1.5.1 Steady-State Techniques.- 4.1.5.2 Methods of Pre-Steady-State Kinetics.- 4.1.6 Deviations from the Michaelis-Menten Kinetics.- 4.2 Relationship of Rate and Equilibrium.- 4.3 Specificity.- 4.3.1 General Characteristics.- 4.3.1.1 Types of Cleavable Bonds.- 4.3.1.2 Position Specificity.- 4.3.1.3 Primary Specificity.- 4.3.1.4 Secondary Specificity.- 4.3.1.5 Tertiary and Quaternary Specificity. Limited Proteolysis.- 4.3.2 Quantitative Dependences of Substrate Structures and Their Reactivity.- 4.3.2.1 Statistical Analysis of Specificity.- 4.3.2.2 Linear Free-Energy Type Relationship.- 4.3.3 Stereospecificity.- 4.3.4 Relationship Between Catalytic and Michaelis Constants.- 4.4 Efficiency.- 4.5 Comparison of Amide Hydrolase Efficiency and Specificity.- 4.6 Effect of Amide Hydrolases Modification on the Activity.- 4.6.1 Proteolytic Modification.- 4.6.2 Chemical Modification.- 4.6.3 Site-Directed Mutagenesis.- 4.7 Synthetic Activity of Amide Hydrolases.- 4.8 Unusual and Side Reactions Catalyzed by Amide Hydrolases.- 4.8.1 Transpeptidation.- 4.8.2 Oxygen Exchange in the Carboxylic Group of Acylamino Acid.- 4.8.3 Enolization of Ketones, ?, ?-Elimination, etc.- 4.9 Conclusion.- 5 Regulation and Effect of External Factors.- 5.1 Zymogens and Their Activation.- 5.2 The Influence of pH.- 5.2.1 The Kinetics.- 5.2.2 Interpretation of Ionization Constant Values.- 5.2.3 Experimental Data.- 5.3 The Influence of Ions and Ionic Strength of the Solution.- 5.3.1 Specific Ions.- 5.3.2 The Effect of Ionic Strength of the Solution.- 5.4 The Effect of Organic Solvents.- 5.5 The Kinetic Isotope Effect of the Solvent.- 5.6 The Effect of Temperature and Pressure.- 5.6.1 Theory.- 5.6.2 Experimental Data.- 5.6.3 Com