Physical Chemistry of the Life Sciences

BIOCHEMICAL EDUCATION

January 1975 Vol. 3 No. 1

Oxford Biology Readers

DNA Synthesis

E d by J. J. H e a d , O x f o r d U n i v e r s i t y P r e s s .

By A r t h u r K o r n b e r g . W . H. F r e e m a n a n d C o m p a n y , S a n F r a n c i s c o , 1974. P p 399. $ 1 8 . 0 0 .

These booklets usually contain 16 pages of text and illustrations in colour but some are double this size. They deal with a limited area of biology and the authors are usually well known experts in the chosen field. The original intention was, I believe, that they should be aimed at the 17-18 year olds in school. Somehow the standard has slowly crept up so that, even though the complexity of the school biology syllabus is increasing, it would be an exceptionally bright school leaver who understood the more recent texts. Each Reader ends with a section on Further Reading. The price is very modest usually being between 30p and 50p. Since some of the Oxford Biology Readers are concerned with topics in a University Degree course in biochemistry, they are very useful as supplementary reading and it must be hoped that the more enthusiastic students will purchase a handful of Readers even though they cannot afford many text books. I mention below some Readers which may be particularly useful to biochemists. N o . 34. Protein Structure by D. C. Phillips & A. C. T. North, 1973.60p. This is a splendid publication. It contains figures in stereo so that red and green spectacles are provided. After considering the different amino acids they show the primary structure of insulin and then turn to the three dimensional structure of proteins. This leads into the a-helix and /l-sheets of which there are nice 3-D figures. The structure of collagen is considered before moving on to the globular proteins, myoglobin and lysozyme. The latter of course is the special pride of the authors and they go to town with 3-D figures showing how the enzyme and substrate interact. They end with a brief but revealing consideration of the genetic code and a cunning figure that shows that amino acid residues of the same general type tend to have similar codons. A splendid booklet that could well be used as the core of a series of lectures. N o . 5 8 . L y s o s o m e s by A. C. A l l i s o n , 1 9 7 4 . 3 0 p . The illustrations in this Reader are exceptionally good and could usefully supplement a lecture on the subject. (I do not, however, like legends in yellow for I find them difficult to read.) Allison who is an expert in this field deals first with the identification and preparation of lysosomes, their enzyme activity, and then their function. Here he deals with autophagy, development, repression of tissue necrosis, hormone secretion and white blood cells. He then turns to congenital abnormalities affecting lysosomes, i.e. inborn errors of metabolism. If one has not got a film available showing the phenomenon of degranulation in polymorphs this booklet would be a good way of convincing a group of students of the importance of lysosomes. N o . 75. T r a n s c r i p t i o n o f D N A by A . A. T r a v e r s , 1 9 7 4 . 3 0 p . It must have been difficult for one so closely involved with progress in this field to write an article limited to 16 pages including many beautifully clear diagrams. Since this Reader carries a 1974 publication date it is not surprising that even semi-experts will learn a good deal not only about recent research but also how best to present this fascinating but complex story. Especially welcome is a clear account of the role of sigma factor, the control of ribosomal RNA synthesis in bacteria and prog r a m m e d transcription. N o . 79. Hormones and cell metabolism by P. J. R a n d l e a n d R. M . D e n t o n , 1 9 7 4 . 3 0 p . The examples of hormone action are largely confined to a small n u m b e r of animal hormones and to their effects on carbohydrate and fat metabolism in m a m m a l s . After a necessary survey of carbohydrate metabolism, the hormone cycle is described; by this is meant the way the components of the system determine the concentration of the hormone in extracellular water. This leads on to cyclic A M P and the second messenger hypothesis. The diagrams are excellent and will be a great help in teaching this intriguing subject. Once again I found the legends in yellow a bad mistake. P. N. Campbell

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This book should prove extremely valuable for both teaching and research purposes. The author first summarizes the major facts clearly and concisely, then provides the detailed experimental basis for these facts. He has included numerous figures which clearly illustrate both the original data and the models that have been inferred from them. Particularly useful are the many tables where the author has summarized data from numerous sources, so that the reader can quickly grasp the relationships between diverse, but related, enzymes and systems. The organization of the material is orderly and logical, and should provide the reader wilh an appreciation of the current state of knowledge, as well as its historical development. I recommend this book for use with any course in which the structure, synthesis and metabolism of DNA comprise a major part. Research workers should also find this book very useful. Sufficient detail is provided for reference purposes, and literature citations on each page will direct the reader to the original sources where necessary. Although emphasis is placed on the enzymes and other proteins actually involved in the synthesis of DNA, the roles of DNA in RNA synthesis, recombination, and other aspects of metabolism are discussed where relevant. The literature cited is sufficiently current (through early 1974), and enough unpublished results are described to insure that all but the most recent published work is included. Anyone interested in DNA research should find this book worthwhile reading. Huber Warner Department of Biochemistry University of Minnesota St. Paul Minnesota SS101. U.S.A.

Physical Chemistry of the Life Sciences By G . M . B a r r o w . M c G r a w - H i l l P p 406. £ 6 . 8 5 .

Book Company.

1974.

At a time when the decision of many students to study the life sciences is accompanied by a somewhat negative attitude towards the physical sciences, there is a real need for a sound but sympathetic approach to the teaching of physical chemistry as part of a life sciences course. Many of the tools used today in biological research require such a background for their competent use and, further, there is m u c h to be discovered about biological systems by applying a quantitative physico-chemical approach. Professor Barrow has tried to convey this approach by selecting from a standard physical chemistry course the aspects which are most likely to be of value in approaching biological systems and arranging them under three sections on Molecular Structure, Energy and Equilibria, and Kinetics. In the first he provides a good background to spectroscopy of small molecules which should take the non-mathematical reader well in to the fundamentals of energy states, q u a n t u m restrictions and the wave nature of particles. The chapter on X-ray diffraction is good, although the use of isomorphous replacement is not discussed. The treatment of nuclear magnetic resonance spectroscopy is excellent. There are two chapters on molecules in liquids but no discussion of the nature of properties of water and its role in biological systems. Just as for the Ancient Mariner, its only acknowledged role is that of keeping ions apart. The second section on Energy and Equilibria is clear and well presented and the thermodynamic and statistical approaches to entropy are particularly good. Some people will be less happy when standard electrode potentials are used to describe equilibria between pyruvate and lactate, etc., and others will despair when phosphate-group transfer potentials are used as a third way of quantitating certain equilibria. It would cause m u c h less confusion,

18

BIOCHEMICAL EDUCATION

at least in biochemistry, if free energies were used for all such reactions. The final section on Kinetics deals with rates and mechanisms of chemical reactions, including enzyme-catalysed reactions, the stationary-state method and theories of the elementary reaction process. The final chapter on rates of transport processes contains introductions to diffusion, sedimentation velocity, sedimentation equilibrium and electrophoresis. The treatment here is not always clear as, for example, when v (termed the 'specific volume') in the buoyancy correction term is implied as representing the reciprocal of the density of the dry solute. Values of M derived from the Svedberg equation, it is suggested, are affected by the molecular shape owing to the entry of the diffusion coefficient! In general, this book provides an abridged and simplified physical chemistry course. Few examples are taken from the life sciences and, with a few exceptions, the student is left to make his own connections with biological molecules and systems. It is no criticism of the author to say that the book appears to be written by a physical chemist looking into the life sciences from outside. Whether this will meet the need of the average biochemistry student, however, is questionable. S.I. units are ignored. The errors are few and one will even help to c o m m e n d the book to zoologists: the relation on the inside cover which states 1 m o l e / h r = 44.7 cm/sec. R. H. Pain Department of Biochemistry The University Newcastle-upon-Tyne, U.K.

The Molecules of Nature - - A Survey of the Biosynthesis and Chemistry of Natural Products By James B. Hendrickson. Pp. 189. W. A. Benjamin, Inc., Advanced Book Program, Reading, Mass. Third printing with corrections. 1973 (paperback) $6.50. This is a brief m o n o g r a p h intended for undergraduate students in chemistry. Within these limits, it is an excellent introduction to the subject, and would also make useful reading for workers in other branches of chemistry and biology. Chapter 1 represents a very brief introduction with further recommended reading. In chapter 2, the biosynthesis of phenylpropanes, acetogenins, terpenes, steroids and alkaloids is reviewed, while chapters 3, 4 and 5 are devoted to the chemistry of these compounds. The approach is that of the organic chemist, who is interested in the structure and genesis of natural products. There is no enzymology, and, for example, the biosynthesis of the aromatic ring, which is a biochemical classic of genetics and enzymology, is accorded a brief half page chemical description. Thus, all the problems discussed are chemical rather than biological, and the reader becomes aware of the great range of sophisticated methods now available to the chemist for the structural determination of organic molecules. However, the author does not neglect the classical proofs of structure of some of the longer known natural products, such as strychnine, morphine, and more recently terramycin. The mechanisms of molecular rearrangement proposed for certain biogenic reactions are also appropriately discussed. Although investigations with isotopic tracers are described, they might have been given far greater emphasis. There is the slight danger that a student could read this book without appreciating fully the tremendous contribution made by isotopic studies in this field. The text is arranged so that problems arise in the natural course of discussion. A special stop m a r k in the text is found at the end of the presentation of evidence, but before the solution. This extremely attractive technique fits in well with the tone of the book, which puts the interests and requirements of the undergraduate chemistry student foremost. T. A. Scott

J a n u a r y 1975 Vol. 3 No. 1

Physics for the Life Sciences By Alan H. Cromer. McGraw Hill Inc., N.Y. Pp 498. 1974. £6.55. It is not easy to teach physics to biologists; physics is an exact quantitative science and many of its most important concepts can readily be explained and related only by the use of mathematics, which many biology students find difficult. The professional physicist normally not only finds mathematics easy, but he finds the explanation of a scientific phenomenon in terms of a succinct mathematical expression to have a beauty of its own. One approach to teaching physics to life scientists is to press on with true missionary zeal and utter mathematical rigour in the confidence that anybody brought face to face with beauty must recognize it (in any case, a little discipline is of great benefit). The alternative is for the teacher to impose a little discipline on himself - - how far c a n one go in explaining the subject without making it unintelligible to the non-mathematician? This second approach really does require some effort but is frequently worthwhile for the teacher himself - the physicist will often accept the mathematical expression as the reality behind a phenomenon without worrying about what it means in physical terms (for example, just what is the physical meaning behind the mathematical device of resolving a plane-polarized ray of light into two components with opposite circular polarization?) ! am sure that the second approach is the realistic one and that there is only one way of making it effective - - by clear exposition and copious illustrations; Professor Cromer's book is exemplary in these respects. A second problem encountered in trying to teach a subject at elementary level to mature students is the level of knowledge that is taken for granted at the start, and no two people would necessarily agree on this; but I can only say that Professor Cromer seems to me to have been quixotic in some of his decisions - - for instance, I was amazed that, in a book that makes a valiant attempt to put across some feeling for the ideas of nuclear forces and relativity, an appendix included an illustrated paragraph on how to use a protractor. More importantly, I read the first seventy or so pages of the book, which are devoted to the principles of measurement and dimensions and to Newtonian mechanics, with an ever-growing sense of puzzlement - - why, oh why, had Professor Cromer worked out most of his examples in pounds, feet and inches? I know that the Americans have been even more reluctant to abandon Imperial units than the British, but surely American schools use the metric system for science at least? Then, on page 72, all became clear - the pound is of course a unit of force whereas the gram is a unit of mass. and Professor Cromer had been putting off for as long as possible the need to explain the difference between mass and weight. This circumvention is I think ill-judged both in principle and in practice; I have never found the difference between the concept of mass, the quantity of matter in an object, and weight, the force exerted by the earth on it, to be a stumbling block. Moreover, there is now a whole generation of British schoolchildren who have been brought up entirely on the metric system and surely the Americans cannot be far behind - - they are going to be much more confused by the use of Imperial units than they ever would by being told about mass at the outset. The choice of material to~be included in a book on Physics for the Life Sciences obviously depends on the group of students being considered - - Professor Cromer lists students in biology, pharmacy, pre-medicine, physical therapy, physical education and the allied health sciences in his Preface and this has doubtless led to a different balance of book from one aimed purely at biologists. Presumably the needs of the physical therapists and physical education students were partly responsible for what seems to me an over-long and sometimes laboured section on mechanics. But in a n u m b e r of cases the author develops the basis of some aspect of physics very well, but stops short of completing its application in biology. For example, he has an excellent section on wave phenomena, including the superposition of waves, which he illustrates mainly with reference to sound waves (not I think of enormous importance to his intended readership); why did he not exploit this foundation by elaborating the principles of the microscope, surely still one of the most important and widely-used physical instru-