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Understanding enzymes (2nd edition)
TIBS 11 - March 1986
126
All about
Enzymes
Understanding Enzymes (2nd Edition) by Trevor Palmer, Ellis Horwood, 1985. £13.75 (411 pages) ISBN 0 85312 874 X Enzymology is no longer a fashionable area of biochemistry, but it would be hard to conceive of an adequate course in biochemistry that did not include a substantial amount of enzymology, and it continues to be a necessary component in biotechnology and other rapidly developing areas of the subject. Consequently it remains an important objective for any biochemistry student to achieve some understanding of enzymes, even if it is based only on the rather halfhearted accounts to be found in typical general textbooks of biochemistry. For many years I had the impression that the authors of these textbooks did not believe in zwitterions: the usual practice was to introduce the structure of proteins in relation to impossible neutral structures, follow this by a paragraph or two with a ritual appearance of zwitterions, probably to satisfy a pedantic physical chemist who suggested that the true structure should at least be mentioned, and then return to incorrect structures for the rest of the book, thereby making it clear that the author didn't believe a word of it. This sort of thing is becoming quite rare, but there is still at least one example to be found among well-known textbooks. A second characteristic, also becoming rarer, though more slowly, was to illustrate the Michaelis-Menten equation with a plot of rate against concentration showing the rate reaching the limiting rate at a substrate concentration about ten times the Michaelis constant. Both of these are sometimes regarded as pedantic criticisms, but I do not believe that they are, because I do not see how students can be expected to understand the very mild chemical nature of proteins if they are taught that they are both carboxylic acids and primary amines, and there would be little point in troubling with linear transformations of the Michaelis-Menten equation if one could obtain its parameters by direct measurement. Accordingly, it has long been my habit, on meeting a new textbook, to see how these points are dealt with. Understanding Enzymes presents the ionic structure of amino acids and proteins in a rather puzzling way: sometimes, and indeed on the first mention, they appear in appropriate ionic
states, but elsewhere, including the section in which the structures are formally described, they appear in neutral states. The Michaelis-Menten equation is illustrated twice by rough sketches that suggest that the rate reaches the limit at about twelve times the Michaelis constant, and in this connection one cannot forbear to mention that the technical quality of some of the illustrations is among the lowest I have ever seen in a book offered by a reputable publisher. Despite these criticisms, there is an astonishing amount of information packed into the book's 400 pages, including a fairly thorough account of enzyme kin-
etics beyond the level found in most general textbooks, and a useful account of the medical and industrial importance of enzymes. (But I hope that some day someone will explain why it is apparently not possible to discuss clinical uses of enzymes without hiding them behind names like AST, formerly known to clinical chemists as GOT.) Many of the chapters are concluded with problems, which are both well thought-out and discussed in detail in the back of the book. ATHEL CORNISH-BOWDEN
Department of Biochemistry, University of Birmingham, PO Box 363, Birmingham BI5 2TT, UK.
Valuable biochemistry text for clinicians Biochemical Basis of Medicine by Eric D. Wills, John Wright & Sons, 1985, £14.95 (xxi + 631 pages) ISBN 0 7236 0722 2 Completion of his life's work as a teacher and scientist in the form of a comprehensive text should be deeply satisfying for the author. According to a publisher's note accompanying the Biochemical Basis of Medicine, Professor Eric D. Wills never saw his finished book; he died but a few hours before the first copies were received from the press. Nonetheless, he has left a valuable legacy to students and teachers of medicine who are certain to appreciate his attempt to show 'the great importance and significance of the subject in medicine'. The contents are in five parts: (1) biochemistry of the cell, including membrane structure and metabolism and functions of subcellular organeUes; (2) whole-body metabolism, including nutrition and digestion, hormones, plasma glucose, lipids, amino acids and electrolytes; (3) tissue metabolism, including blood, liver, kidney, muscle, bone and brain; (4) detoxication, including metals, xenobiotics, alcohol and carcinogens; and (5) diagnosis, including enzymology, biochemical genetics, immunology and chemotherapy. The text is quite comprehensive in dealing with medical applications and relations to other disciplines, such as physiology and pharmacology; but there are lamentable omissions, such as reproduction, estrogen and androgen actions, gene regulation, and recombinant DNA. Moreover, the author has deliberately limited the amount of basic biochemical information. In some cases, structures and pathways are relegated to an appendix, on the premise that other texts
cover such topics as protein synthesis and basic metabolic pathways. However, the appendix treatment for enzyme kinetics is quite daunting for a student with no previous experience of the subject; for example, the outline for 13-oxidation of fatty acids is quite uninformative and confusing for such students. The book is ideal for students who have had an introductory course in biochemistry at the level of Stryer or Lehninger. They will seek in vain in the index for enzyme regulation, mechanisms of insulin action and gene transcription and translation. In spite of the above limitations, this book has much to recommend it, and teachers of the subject would do well to consider seriously the syllabus it follows. With the judicious application of 'refresher' material on basic mechanisms, and addition of some clinical cases and problems to be solved, the book could be an excellent teaching manual for instructors. On the whole, the text is clear and concise, though tending towards a somewhat telegraphic, didactic style. It might have been enlivened by more of the topical argumentative approach of the excellent nutrition sections, and some of the currently controversial areas, such as megavitamin usage, would have added interest. Each instructor will doubtless find some area of his own interest that he feels is neglected or distorted, but on the whole this book is a great achievement for one author, providing a quite up-to-date survey of major aspects of biochemistry that are relevant to clinical studies. For students, or medical practitioners who wish to refresh their knowledge, the presentation is eminently readable. The sections are remarkably self-contained,
126
All about
Enzymes
Understanding Enzymes (2nd Edition) by Trevor Palmer, Ellis Horwood, 1985. £13.75 (411 pages) ISBN 0 85312 874 X Enzymology is no longer a fashionable area of biochemistry, but it would be hard to conceive of an adequate course in biochemistry that did not include a substantial amount of enzymology, and it continues to be a necessary component in biotechnology and other rapidly developing areas of the subject. Consequently it remains an important objective for any biochemistry student to achieve some understanding of enzymes, even if it is based only on the rather halfhearted accounts to be found in typical general textbooks of biochemistry. For many years I had the impression that the authors of these textbooks did not believe in zwitterions: the usual practice was to introduce the structure of proteins in relation to impossible neutral structures, follow this by a paragraph or two with a ritual appearance of zwitterions, probably to satisfy a pedantic physical chemist who suggested that the true structure should at least be mentioned, and then return to incorrect structures for the rest of the book, thereby making it clear that the author didn't believe a word of it. This sort of thing is becoming quite rare, but there is still at least one example to be found among well-known textbooks. A second characteristic, also becoming rarer, though more slowly, was to illustrate the Michaelis-Menten equation with a plot of rate against concentration showing the rate reaching the limiting rate at a substrate concentration about ten times the Michaelis constant. Both of these are sometimes regarded as pedantic criticisms, but I do not believe that they are, because I do not see how students can be expected to understand the very mild chemical nature of proteins if they are taught that they are both carboxylic acids and primary amines, and there would be little point in troubling with linear transformations of the Michaelis-Menten equation if one could obtain its parameters by direct measurement. Accordingly, it has long been my habit, on meeting a new textbook, to see how these points are dealt with. Understanding Enzymes presents the ionic structure of amino acids and proteins in a rather puzzling way: sometimes, and indeed on the first mention, they appear in appropriate ionic
states, but elsewhere, including the section in which the structures are formally described, they appear in neutral states. The Michaelis-Menten equation is illustrated twice by rough sketches that suggest that the rate reaches the limit at about twelve times the Michaelis constant, and in this connection one cannot forbear to mention that the technical quality of some of the illustrations is among the lowest I have ever seen in a book offered by a reputable publisher. Despite these criticisms, there is an astonishing amount of information packed into the book's 400 pages, including a fairly thorough account of enzyme kin-
etics beyond the level found in most general textbooks, and a useful account of the medical and industrial importance of enzymes. (But I hope that some day someone will explain why it is apparently not possible to discuss clinical uses of enzymes without hiding them behind names like AST, formerly known to clinical chemists as GOT.) Many of the chapters are concluded with problems, which are both well thought-out and discussed in detail in the back of the book. ATHEL CORNISH-BOWDEN
Department of Biochemistry, University of Birmingham, PO Box 363, Birmingham BI5 2TT, UK.
Valuable biochemistry text for clinicians Biochemical Basis of Medicine by Eric D. Wills, John Wright & Sons, 1985, £14.95 (xxi + 631 pages) ISBN 0 7236 0722 2 Completion of his life's work as a teacher and scientist in the form of a comprehensive text should be deeply satisfying for the author. According to a publisher's note accompanying the Biochemical Basis of Medicine, Professor Eric D. Wills never saw his finished book; he died but a few hours before the first copies were received from the press. Nonetheless, he has left a valuable legacy to students and teachers of medicine who are certain to appreciate his attempt to show 'the great importance and significance of the subject in medicine'. The contents are in five parts: (1) biochemistry of the cell, including membrane structure and metabolism and functions of subcellular organeUes; (2) whole-body metabolism, including nutrition and digestion, hormones, plasma glucose, lipids, amino acids and electrolytes; (3) tissue metabolism, including blood, liver, kidney, muscle, bone and brain; (4) detoxication, including metals, xenobiotics, alcohol and carcinogens; and (5) diagnosis, including enzymology, biochemical genetics, immunology and chemotherapy. The text is quite comprehensive in dealing with medical applications and relations to other disciplines, such as physiology and pharmacology; but there are lamentable omissions, such as reproduction, estrogen and androgen actions, gene regulation, and recombinant DNA. Moreover, the author has deliberately limited the amount of basic biochemical information. In some cases, structures and pathways are relegated to an appendix, on the premise that other texts
cover such topics as protein synthesis and basic metabolic pathways. However, the appendix treatment for enzyme kinetics is quite daunting for a student with no previous experience of the subject; for example, the outline for 13-oxidation of fatty acids is quite uninformative and confusing for such students. The book is ideal for students who have had an introductory course in biochemistry at the level of Stryer or Lehninger. They will seek in vain in the index for enzyme regulation, mechanisms of insulin action and gene transcription and translation. In spite of the above limitations, this book has much to recommend it, and teachers of the subject would do well to consider seriously the syllabus it follows. With the judicious application of 'refresher' material on basic mechanisms, and addition of some clinical cases and problems to be solved, the book could be an excellent teaching manual for instructors. On the whole, the text is clear and concise, though tending towards a somewhat telegraphic, didactic style. It might have been enlivened by more of the topical argumentative approach of the excellent nutrition sections, and some of the currently controversial areas, such as megavitamin usage, would have added interest. Each instructor will doubtless find some area of his own interest that he feels is neglected or distorted, but on the whole this book is a great achievement for one author, providing a quite up-to-date survey of major aspects of biochemistry that are relevant to clinical studies. For students, or medical practitioners who wish to refresh their knowledge, the presentation is eminently readable. The sections are remarkably self-contained,