Proteolysis is an irreversible posttranslational modification affecting each and every protein from its biosynthesis to its degradation. Limited proteolysis regulates targeting and activity throughout the lifetime of proteins. Balancing proteolysis is therefore crucial for physiological homeostasis. Control mechanisms include proteolytic maturation of zymogens resulting in active proteases and the shut down of proteolysis by counteracting endogenous protease inhibitors. Beyond the protein level, proteolytic enzymes are involved in key decisions during development that determine life and death – from single cells to adult individuals. In particular, we are becoming aware of the subtle role that proteases play in signaling events within proteolysis networks, in which the enzymes act synergistically and form alliances in a web-like fashion. Proteases come in different flavors. At least five families of mechanistically distinct enzymes and even more inhibitor families are known to date, many family members are still to be studied in detail. We have learned a lot about the diversity of the about 600 proteases in the human genome and begin to understand their physiological roles in the degradome. However, there are still many open questions regarding their actions in pathophysiology. It is in this area where the development of small molecule inhibitors as therapeutic agents is extremely promising. Approaching proteolysis as the most important, irreversible post-translational protein modification essentially requires an integrated effort of complementary research disciplines. In fact, proteolytic enzymes seem as diverse as the scientists working with these intriguing proteins. This book reflects the efforts of many in this exciting field of research where team and network formations are essential to move ahead.

Viral Proteases and Their Inhibitors provides a thorough examination of viral proteases from their molecular components, to therapeutic applications. As information on three dimensional structures and biological functions of these viral proteases become known, unexpected protein folds and unique mechanisms of proteolysis are realized. This book investigates how this facilitates the design and development of potent antiviral agents used against life-threatening viruses. Users will find descriptions of each virus that detail the structure and function of viral proteases, discuss the design and development of inhibitors, and analyze the structure-activity relationships of inhibitors. This book is ideal biochemists, virologists and those working on antiviral agents. Provides comprehensive, state-of-the-art coverage of virus infections, the virus lifecycle, and mechanisms of protease inhibition Analyzes structure-activity relationships of inhibitors of each viral protease Presents an in-depth view of the structure and function of viral proteases

Handbook of Proteolytic Enzymes, Second Edition, Volume 1: Aspartic and Metallo Peptidases is a compilation of numerous progressive research studies on proteolytic enzymes. This edition is organized into two main sections encompassing 328 chapters. This handbook is organized around a system for the classification of peptidases, which is a hierarchical one built on the concepts of catalytic type, clan, family and peptidase. The concept of catalytic type of a peptidase depends upon the chemical nature of the groups responsible for catalysis. The recognized catalytic types are aspartic, cysteine, metallo, serine, threonine, and the unclassified enzymes, while clans and families are groups of homologous peptidases. Homology at the level of a family of peptidases is shown by statistically significant relationship in amino acid sequence to a representative member called the type example, or to another member of the family that has already been shown to be related to the type example. Each chapter discusses the history, activity, specificity, structural chemistry, preparation, and biological aspects of the enzyme. This book will prove useful to enzyme chemists and researchers.

Structure–Function Relationships of Proteolytic Enzymes provides information pertinent to the fundamental aspects of proteolytic enzymes. This book presents the historical role of proteolytic enzyme as a group in protein and enzyme chemistry. Organized into 23 chapters, this book begins with an overview of the results obtained from investigation on the chymotrypsinogens of porcine origin. This text then examines the differences of amino acid sequence between chymotrypsin, trypsin, and elastase that affect the substrate binding site, which reflect the specificity differences between these enzymes. Other chapters consider the kinetic parameters related to the trypsin-catalyzed hydrolysis of several model peptides. This book discusses as well the acetylation of trypsin, which result in functional consequences varying from complete inactivation to promotion of activity. The final chapter deals with the physical properties of stem bromelain in comparison with the data for three other sulfhydryl proteases of plant origin. This book is a valuable resource for enzymologists, microbiologists, and biochemists.

Methods included in this volume apply to the expression and characterization of retroviral proteases and their inhibitor/substrate design.

The remarkable expansion of information leading to a deeper understanding of enzymes on the molecular level necessitated the development of this volume which not only introduces new topics to The Enzymes series but presents new information on some covered in Volume I and II of this edition.