Comparative Enzymology Of Cholinesterases

The Fifth International Meeting on Cholinesterases convened in Madras, India, in September of 1994. The long and rich history and culture of India provided an excellent setting for the meeting. More than 120 delegates from Asia, Australia, Europe and North America heard 54 oral presentations and viewed 54 posters on current research on enzymes of the cholinesterase family. The aim of this book is to compile the presentations of the Fifth International Meeting on Cholinesterases into a volume that describes recent investigations on the structure and catalytic function of acetylcholinesterase (AChE), butyrylcholinesterase (BuChE) and related enzymes, as well as studies on the molecular and cellular biology of these enzymes and the genes which encode them. Cholinesterases enjoy a long and storied history in diverse areas. In basic biochemical research, AChE is one of the best studied, though yet enigmatic, of enzymes. The efficient catalytic function of this enzyme presents the biochemist with a fundamental challenge in understanding the relationship between structure and function. AChE and BuChE belong to a family of proteins, the alB hydrolase fold family, whose constituents evolutionarily diverged from a common ancestor. Proteins in this family have a wide range of physiological functions. In commerce, AChE is a prime target for agricultural insect control, and for the development of therapeutic agents for Alzheimer's disease.

Although the anticholinesterase (anti-ChE) agents have only limited applica tions in therapy, and from the viewpoint of practical significance they are more appropriately classified as toxic compounds or insecticides than as drugs, in their capacity of pharmacological tools they have few equals. The concept of neuro humoral transmission was originally established largely from experiments in which physostigmine, or eserine, was employed to protect acetylcholine (ACh), the trans mitter of the cholinergic nerves, from rapid hydrolytic destruction by acetyl cholinesterase (AChE) and other cholinesterases (ChE's). Since then, a great num ber of additional reversible and irreversible anti-ChE agents also have been indis pensable in studies of synaptic and neuroeffector transmission, and of other physiological processes. At the same time, there is practically no other class of compounds for which a mechanism of pharmacological action can be described in such concrete biochemical and physiological terms. Consequently, it is not sur prising that a huge literature has developed on these several closely interdependent topics. The assembling anrl proper correlation of this material for the present volume has taken the collaborative efforts of over two dozen . investigators. It iR believed that their contributions to this end will prove invaluable to future in vestigators in providing a ready, inclusive source of established information, in defining areas where further studies are indicated, and in preventing unnecessary duplication of past work. How well these aims have been accomplished will be for time and the reader to judge.

It is a pleasure to have the privilege of writing the foreword for a book edited by Dr. Francis F. Foldes. Dr. Foldes has collected in one convenient place a discussion and description of enzyme systems of use to the anesthesiologist and to those other individuals, such as undergraduate and graduate students in related basic sciences, who will profit by and can make use of this body of information. The practicing anesthesiologist and those who work in related fields have become increasingly aware of the need to understand enzyme activities which influence the uptake, distribution, and excretion of those substances that are used in the anesthetic management of surgical patients. A variety of such is obvious when one considers that such diverse substances as activities and muscle re analgesic drugs, tranquilizers, hypnotics, anesthetic agents, laxants are strongly affected by these systems and have an influence over the basic understanding of how these drugs operate and act in the body, as well as providing a safety measure so necessary to the proper conduct of clinical anesthesia. The editor and his colleagues have rendered us a great service in collecting information that deals with the basic activity of enzymes including their structure, their kinetics, and to the degree that knowledge permits, mechanism of actions.

Modern Trends in Physiological Sciences, Volume 3: Cholinesterases: A Histochemical Contribution to the Solution of Some Functional Problems covers the histochemical aspects of humoral and tissue cholinesterases, both inside and outside of the nervous system. This volume is composed of three part encompassing 14 chapters. The first part describes the link between cholinesterases and serum and between acetylcholinesterase and erythrocytes. This part also deals with the histochemical measurement of acetylcholinesterase activity in the erythrocytes or platelets of some mammalian species, with an emphasis on delineating the possible role of this enzyme in maintaining the integrity of these cells. The remaining two parts discuss the convergence of morphological, physiological, and biochemical research on tissue cholinesterases. These parts also describe the general features of the localization of cholinesterases at nerve-endings in tissues and organs. Histochemical investigations of tissular cholinesterases outside the nervous system, such as in smooth muscle fibers, are also presented. This book will be of value to physiologists, enzyme scientists and researchers, cell biologists, and histochemists.

Reviews of Environmental Contamination and Toxicology provides detailed review articles concerned with aspects of chemical contaminants, including pesticides, in the total environment with toxicological considerations and consequences.