Kinetics Of Enzyme Modifier Interactions

The kinetic mechanisms by which enzymes interact with inhibitors and activators, collectively called modifiers, are scrutinized and ranked taxonomically into autonomous species in a way similar to that used in the biological classification of plants and animals. The systematization of the mechanisms is based on two fundamental characters: the allosteric linkage between substrate and modifier and the factor by which a modifier affects the catalytic constant of the enzyme. Combinations of the physically significant states of these two characters in an ancestor-descendant-like fashion reveal the existence of seventeen modes of interaction that cover the needs of total, partial and fine-tuning modulation of enzyme activity. These interactions comprise five linear and five hyperbolic inhibition mechanisms, five nonessential activation mechanisms and two hybrid species that manifest either hyperbolic inhibition or nonessential activation characteristics depending on substrate concentration. Five essential activation mechanisms, which are taxonomically independent of the mentioned basic species, complete the inventory of enzyme modifiers. Often masked under conventional umbrella terms or treated as anomalous cases, all seventeen basic inhibition and nonessential activation mechanisms are represented in the biochemical and pharmacological literature of this and the past century, either in the form of rapid or slow-onset reversible interactions, or as irreversible modification processes. The full potential of enzyme inhibitors and activators can only be appreciated after elucidating the details of their kinetic mechanisms of action exploring the entire range of physiologically significant reactant concentrations. This book highlights the wide spectrum of allosteric enzyme modification in physiological occurrences as well as in pharmacological and biotechnological applications that embrace simple and multiple enzyme-modifier interactions. The reader is guided in the journey through this still partly uncharted territory with the aid of mechanistically-oriented criteria aimed at showing the logical way towards the identification of a particular mechanism.

This text covers the field of steady-state kinetics from basic principles to the control of the multi-enzyme systems which constitute metabolic pathways. Emphasis is placed on the interpretation of the kinetic behaviour of enzyme-catalyzed reactions in terms of mechanisms. Algorithms are developed which can be implemented in computer programs for the derivation of equations. The treatment of steady-state enzyme kinetics is extended to allosteric enzymes and subunit interactions in polymeric enzymes. Principles are presented which provide for mathematical analysis of the control of multi-enzyme systems. Problems are included at the end of each chapter and their solutions are found at the end of the book. This book will be a useful text for advanced undergraduates and graduate students taking courses in enzyme chemistry and enzyme kinetics.

Principles of Enzyme Kinetics discusses the principles of enzyme kinetics at an intermediate level. It is primarily written for first-year research students in enzyme kinetics. The book is composed of 10 chapters. Chapter 1 provides the basic principles of enzyme kinetics with a brief discussion of dimensional analysis. Subsequent chapters cover topics on the essential characteristics of steady-state kinetics, temperature dependence, methods for deriving steady-state rate equations, and control of enzyme activity. Integrated rate equations, and introductions to the study of fast reactions and the statistical aspects of enzyme kinetics are provided as well. Chemists and biochemists will find the book invaluable.

Annotation This text for advanced courses in enzyme chemistry and enzyme kinetics covers the field of steady-state enzyme kinetics from the basic principles inherent in the Michaelis-Menten equation to expressions that describe the multi-substrate enzyme reactions, providing a framework for the study of enzymes with the aid of kinetic studies of enzyme-catalyzed reactions. Discussion encompasses chemical kinetics, kinetics of monosubstrate reactions, and cooperative and allosteric effects. The editor is affiliated with the University of Novi Sad. Annotation (c)2003 Book News, Inc., Portland, OR (booknews.com).

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.

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.

Biomaterials have been used for artificial-organ and bioreactor materials, and have gained importance for enhancement of human welfare. This book summarizes research devoted to creating useful biofunctional materials by chemical modification of natural polymers, and forecasts future development.