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This book is not intended to be a textbook of biochemistry in the conventional sense. There is no shortage of good biochemistry textbooks, which outline how biochemical knowledge has been gained, trace the logical and experimental developments in this field and present advances in their historical sequence.
In contrast, this book tries to condense important aspects of current knowledge. Its goal is to give concise information on the metabolic sequences in the pathways, the chemistry and enzymology of conversions, the regulation of turnover and the effect of disorders. This concentration on the sequence of facts has entailed the omission of researchers' names, experimental methods and the discussion of how results have been obtained. For information on these aspects, and for an introduction into the fundamentals of biological science, it is necessary to consult textbooks. The scope of this book is general biochemistry, encompassing bacteria (and to some extent archaea), plants, yeasts and animals. Although a balanced representation is intended, personal interest naturally plays a role in the selection of topics. In a number of cases, the chemistry of the reactions is given in more detail, especially at metabolic key and branching points. Human metabolism, its regulation and disorders as a result of disease is a frequent topic. On the other hand, some chapters are especially devoted to bacterial metabolism. This book grew out of my interest in metabolic interrelationships and regulation which was stimulated by my professional work at Boehringer Mannheim GmbH, Germany. Previously, this interest led me to compile the "Biochemical Pathways" wall chart, the first edition of which appeared 30 years ago. Two more editions followed, which have been widely distributed. As a result of this experience, I developed a preference for the graphic presentation of scientific facts. In contrast to texts, figures allow the simultaneous display of different aspects, such as structural formulas, enzyme catalysis and its regulation, the involvement of cofactors, the occurrence of enzymes in various kingdoms of biology, etc. This form of presentation facilitates a rapid overview. A standard set of conventions is used in all figures (representation of formulas, symbols for proteins, the use of colors, the shape of arrows, etc. - the rare exceptions are indicated), and this assists in finding the facts quickly. Tables have been added to provide more detailed information. They list additional properties of the system components, homologies, etc. The text plays only a supportive role. It gives a concise description of the reactions and their regulation, and puts them into the general metabolic context. The arrangement of the text facilitates rapid finding of keywords (underlined), occurrence and location (in italics) and different or alternative metabolic states (listed). Details and discussion of special cases can be distinguished from the main text by the use of smaller print. In many cases, current knowledge focuses on a limited number of species. A rough classification of the occurrence of pathways is given by the color or the reaction arrows in the figures, but both generalizations and specialization are expected to be found in the future, which will necessitate modification of the picture. Clear representation of the multiple interconnections in metabolism poses a difficult task. In the wall chart, which was the precursor of this book, it was frequently necessary to cut off these interconnections in order to retain legibility. The figures in this book provide references to 'key compounds' (e.g., glucose, pyruvate, various amino acids) at the beginning and the end of the pathways in order to place the metabolic sequence into the general context. The interrelationships between these 'key compounds' are shown in the initial Figures 1.1-1 ... 1.1-3 (p. 1 and 2). Likewise, the text contains numerous cross-references to other chapters and sections. They are intended as the textual counterparts to the hyperlinks used in electronic representations. The pertinent decimal classification numbers are shown at the top of each page. The literature references have been limited in number and they usually cite recent review articles and books, if possible, from readily accessible sources. They were selected to provide more detailed information on new developments and additional references for the interested reader. There are no references to long-established biochemical facts which can be found in any textbook. I hope that this restriction will be acceptable to readers, since a complete listing of all sources for the statements presented here would take up a major portion of this volume. To compensate for the omission of such general references, a special chapter on electronic data banks and major printed sources has been added at the end of the book. This work could not have been compiled without the expert knowledge and the contributions of many coauthors, whose names are listed at the beginning of this book. They have written a considerable number of the sections. I wish to thank all of them most gratefully for their work and for their open, committed cooperation. Likewise, I would like to express my best thanks to the scientists who have checked various chapters of the manuscript and have given their valuable advice on the selection of topics, the type of presentation and a large number of details. Besides the persons listed, I have obtained information from many other colleagues, to whom I am very grateful. Further thanks are due to Spektrum Akademischer Verlag, Heidelberg and especially to Ms. Karin von der Saal who proposed publishing the 'Biochemical Pathways' chart in book form. She has helped me to solve many problems and has constantly furthered this project. I also want to express my thanks to the Universitätsdruckerei Stürtz, Würzburg for their efforts in converting my drafts of the figures into a printable form. The management of Boehringer Mannheim GmbH has often shown interest in the project, even after my retirement, and has supported it especially by providing library services. This is gratefully acknowledged. Most of all I want to thank my wife Dea, who has often encouraged me during the long time required to finish this work. She has given me valuable advice and support in checking the text of the English edition. Without her understanding and her help this book would not have been brought to completion.
Tutzing, June 11, 1998 |