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.

In the past ten years, a number of proceedings of symposia on the structure and function of proteolytic enzymes have been pub lished. Their coverage of acid proteases has been limited, mainly due to the lack of significant new information on the structure of these enzymes. In the last four years, however, the primary and tertiary structures of a number of acid proteases have been deter mined, prompting the need to discuss the meanings of the old data and the possibilities for new experimentations. It was for this purpose that the "Conference on Acid Proteases: Structure, Function, and Biology" was organized. It took place at the University of Oklahoma on November 21-24, 1976. This book is a collection of the main lectures delivered at the Conference. Acid Proteases, by definition refers to a group of proteases having an optimal pH in acidic solutions. The classic examples are pepsin and chymosin. Some catalytic features are obviously shared by these proteases, most notably, their inhibition by pepstatin. The use of active center-directed inactivators such as diazoacetyl norleucine methyl ester and 1,2-epoxy-3-(p-nitrophenoxy)propane has shown that two catalytic aspartyl residues are present in most of these enzymes. These apparent cornmon features have prompted the suggestion by several investigators to name this group of enzymes "aspartyl proteases" or "carboxyl proteases".

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

This volume showcases the most important developments in the area of plasminogen regulation. The book is composed of about 16 chapters dealing with a range of topics including the mechanisms of activation of plasminogen, the structure of plasminogen and plasminogen activators, the role of plasminogen in various physiological and pathological processes (such as tumour growth and progression, wound healing and fibrinolysis) and the interrelationship of the plasmin/MMP proteolytic systems.

This book provides an account of the recent advances in our understanding of the role of proteases under physiological and pathological conditions. It reviews the contributions that have been made in the fields of biochemistry, molecular biology, medicine, agriculture and ecology. In addition there is an account of the growing number of practical applications in biotechnology, reflecting the fact that peptidases are major targets for medical and agricultural purposes. The book shows how the numerous protease structures are essential for drug design. The contributions place special emphasis on cysteine, aspartic and metalloproteases and their role in physiological and certain pathological states. Another focus is the classification and nomenclature of peptidases and a review of those proteases currently under the most intensive investigation. The book provides an informative introduction for teachers and newcomers to the field, such as graduate students, while providing a valuable source of material and ideas for the academic and industrial researcher in areas including biochemistry, medicine, agriculture and biotechnology.