Photosynthesis: Physical Mechanisms and Chemical Patterns

39 Photosynthesis: Physical Mechanisms and Chemical Patterns b y R K C l a y t o n . pp 281. I U P A B Biophysics Series; 4. C a m b r i d g e U n i v e r s i t y Press. 1980. £17.50 (hardback)/£6.95 (paperback) ISBN 0-521-22300-8/0-521-29443--6 Life on this planet depends on the ability of chloroplasts to carry out the conversion of solar energy to the free energy of carbon compounds. This book is one man's attempt to explain and summarize our present state of knowledge about the initial events in this process. The book is divided into four parts. The first describes the historical development of our misunderstanding of the photochemistry of photosynthesis up to 1960, while the second reviews the present knowledge of the compositions, structures and functions of the pigment-protein complexes found in the membranes of chloroplasts and photosynthetic bacteria. Part three deals with charge separation, the subsequent transport of electrons and protons, and oxygen evolution. The last, and shortest part, discusses the formation of ATP and the fixation of carbon dioxide. At the end of each chapter is a list of references for further reading; these lists include references to work published in 1979. The emphasis throughout is on the physical aspects of the early events in the trapping of solar energy. Particularly useful for the reader with scant knowledge of molecular physics are sections explaining very clearly the principles of the various spectroscopic methods used to study energy conversion and migration. This emphasis is to be expected in a book in a series on biophysics, but it dees make the book incomplete for the teaching of photosynthesis. Carbon metabolism is given only a brief treatment, and additional texts would need to be recommended to students to cover this area. There is no discussion of the ecological adaptations shown by higher plants grown under different light regimes. It is to be hoped that later editions will include some discussion of Q cycles and of the recently-discovered role of thylakoid protein phosphorylation in controlling the distribution of excitation energy between the two photosystems. Errors are refreshingly few; they include the mutant 'rubulose' on p 258, cyt. 653 on p 210, and in incorrect description of intermittent illumination on p 122. The book is very readable and is excellent value for money, especially in the paperback version. Highly recommended. R J Ellis Department qf Biological Sciences University qf Warwick Coventry, UK

Mammalian Proteases: A Glossary and Bibliography. Volume I, Endopeptidases b y A J B a r r e t t and J K M c D o n a l d . pp 416. A c a d e m i c Press Inc (London) Ltd. 1980. £13 ISBN 0-12-079501-9 In a small book the authors have gathered together the essential information and bibliography on 103 mammalian endopeptidases. The presentation of information on the same enzymes at some length in review form would have required a large multivolume work and a writing period so long that many of the articles would have been out of date. The form chosen by the authors has great advantages for everyone whose research brings them into contact with this group of enzymes. Each enzyme is summarized in less than a page of text covering source, distribution, action, requirements, substrates, inhibitors, and molecular properties. These points are followed by a brief comment and one or two key references. The bibliography for each entry is then set out alphabetically year by year, including the full title of each article. In all cases it includes papers published in 1979 and in a few instances some dated 198/). This is a remarkable achievement, only possible by the development of a computer-aided systcm for codifying and presenting all the information collected. It is the authors' intetation to update the information in future editions. The classification ofendopeptidases has, for the last twenty years, been based on what is known about the active site. The entries appear in five sections: serine, cysteine, aspartic, metallo- and unclassified proteinases. It may come as a surprise to some readers to realise that fifty-nine entries - - over half the total - - are serine endopeptidascs. They form a group of astonishing diversity and include the cascade systems associated with blood coagulation and complement activity. These are set out, as far as possible, in a logical order based on function. Two other growth areas in this subject concern the cnzymology of protein turnover in mammals and

BIOCHEMICAL EDUCATION 10 (1) 1982

the isolation of synthetic and naturally occurring inhibitors of protemases. No longer can biochemists afford to dismiss cathepsms as a confused and arcane group. Many, possibly all the major ones, have now beeu characterized and the importance of the thiol cnzymcs of this group, cg cathepsins H and B, in initiating proteolysis in lysosomcs is now generally accepted. The bibliography on protcinasc inhibitors is now immense. Some are macromolccules of physiological importance. Others have great experimental interest: chloromcthylkctones, diazmncthylkctones and thc family of diverse inhibitors cmcrging from Professor Umezawa's Institute of Microbial Chemistry in Tokyo, some of which, eg pepstatin, conveniently neatly fit the classification of the enzymes based on catalytic mechanism. Where the information is available, the useful inhibitors for each enzyme are listcd and, likely as not, one of the titles of the articles listed will provide a rcfcrcncc with details of their use. Dr Barrett and Dr McDonald are to bc congratulated on producing such a timely and valuable summary of an increasingly important group of enzymes. The publishers, too, deserve our thanks for keeping the price within the reach of individuals as well as libraries. This volume, and the second on exopeptidases to be published later, deserve a wide circulation. A J Kcnny

Endocytobiology. Endosymbiosis and Cell Biology (A Synthesis o f Recent Research. Proceedings o f the International C o l l o q u i u m on E n d o s y m b i o s i s and Cell Research. T/ibingen, G e r m a n y , April 1980.) Edited by W S c h e m m l e r and H E A Schcnk. pp 1060. Walter dc G r u y t e r , Berlin and N e w York. 1)M190 or $95 ISBN 3-11-008299-3 Endocytobiologists generally hypothesize that the cukaryotc cell evolved by serial incorporation into a developing protoeukaryote of at least two originally free-living prokaryotes, symbioscd aerobic photosynthetic bacteria and blue-green algae becoming irrevocably integrated to the status of mitochondria and chloroplasts respectively; more recently, chloroplasts may alternatively have been derived from eukaryotic endosymbionts. Numerous books and articles have been devoted to this topic during the past fifteen years, comparing the tdtrastructure and physiology of eukaryotic organelles and prokaryotic organisms, while recent international symposia have included Tl, e Cell as a Habitat (1978: Royal Society), Celhdar Interactions in Symbiosis and Parasitism (1978; Biosciences Colloquium, Ohio), Or(gins and Evolution of Eukar),otic lntracellular Organelles (1979; NYAS) and lntracelhdar and Intercelhdar Regulation and Recognition in Algae and Symbionts (1981~; Akad Wiss, G6ttingen). Why, then, was there any need for yet another symposium, the proceedings of which form the contents of the present book? One reason given by the editors is previous lack of intercourse between symbiosis researchers and cell biologists: 'The close analogies bctwecn 1)NAcontaining organclles (mitochondria, plastids) and certain intracelhdar symbionts formed the basis of the Tfibingen Colloquium. The major goal was to produce an extensive survey of these ficlds of study. Only intensive exchange of methods and data between symbiosis researchers and cell biologists will lead to further progress.' This large book certainly provides the survey, in many cases covering highly specialized areas of uhrastructural and biochemical research; the 'intensive interchange of experiences, mcthods and data" presumably took place in T/ibingen but is not recorded hcrc and the subtitle 'A Synthesis of Recent Research' must bc deemed optimistic if not actually misleading. It follows that the places to start reading are the synoptic chapters that come at the ends of the Parts and I especially recommend 1) C Smith's consideration ofendosymbiosis as colonization of an extreme habitat, and F R and J M Whatley on the establishment of organcllcs. After this, the specialist reader will find much of interest on adaption of prokaryotcs and eukaryotes as symbionts in flagellates, ciliatcs, foraminifcrans, coelenterates, flatworms, insects, higher animals and plants, and on the interrelationships between l)NA-organclles, nucleus and cytoplasm. Key words that best indicate thc content of the bulk of these eighty-seven papers are: chloroplasts, mitochondria, cyanellcs, symbiotic bacteria, symbiotic algae, carbon metabolism, plasmids, organcllar I)NA, polysomcs, RNA. The book ends with a useful confrontation between the compartmental hypothesis of eukaryote evolution and the cndocytobiotic hypothesis, whcre H R Mahler's and T Cavalicr-Smith's separate arguments against symbiotic origin of mitochondria read more convincingly than W J H Kunicki-Goldfingcr's proposals of symbiotic origin of nucleus, 9+2 flagella, mitochondria and chloroplasts. (;ordon F Lccdalc