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Book Review Electron Distributions and the Chemical Bond. Edited by P. Coppens and M. B. Hall

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Lipmann, W . D. McElroy, and S . P. Colowick acquaint us
not only with the personality of the scientist, Kaplan, but
also with the stages of his development and the background against which his remarkable achievements unfolded.
Colowick‘s remarks introduce the reader in a subtle way
to the theme of the book, which, in ten chapters, treats evolutionary aspects of pyridine nucleotides as well as the
physico-chemical, synthetic chemical and cell-biological
aspects of NAD and NADP. The classical enzymology of
the dehydrogenases developed by Warburg and his school
is scarcely mentioned. This approach is only applied in the
case of membrane-bound catalysts and non-redox processes with NAD. The functional aspects are dealt with in
terms of X-ray structural analysis together with the application of pyridine nucleotide analogues and of immobilized coenzymes. None of the chapters seeks to be encyclopedic in its completeness, the most important problems
are, nevertheless, discussed and enriched with a literature
selection that is usually representative.
In the first chapter, H . B. White ZZZ develops ideas concerning prebiotic origins and the mode of action of pyridine nucleotides in the early stages of evolution. Structural
features of dehydrogenases, such as the similarity of their
domain structures, are discussed in support of the hypothesis that it was the polypeptide structures that adapted to
the primitive pyridine nucleotide “dehydrogenases” (a
very plausible but not generally accepted assumption).
The second chapter (J. B. A . Ross, S . Subramanian, L.
Brand) describes the present state of knowledge concerning the electronic structure of pyridine nucleotides and
their analysis by absorption, CD, fluorescence and phosphorescence spectroscopy. The chemistry of NAD and
NADH, together with various homologues and analogues
as well as their conformations in solution, are dealt with by
N . J. Oppenheimer in the third, and the synthesis, properties and applications of a large number of synthetic coenzyme analogues by B. M . Anderson in the fourth chapter.
Since this was Kaplan’s field of research for almost 30
years it is not surprising that these topics are given, with
more than 80 pages, an importance that seems a little disproportionate.
In the fifth chapter U. M . Grau presents, with many
clear schemes, a very good description of the interactions
of the pyridine nucleotide coenzymes with the apodehydrogenases, insofar as they can be deduced from X-ray
structural analysis data. The most important aspects of a
fascinating chapter of structural research on enzymes is
given in a condensed but up-to-date form.
The sixth chapter (C.-Y. Lee, A. F. Chen) offers a valuable review to those who are concerned with the problems
of the immobilization of dissociable coenzymes, naturally
with special emphasis on NAD and NADP. Synthetic coupling techniques, general aspects of ligand affinity chromatography and numerous examples of application are
presented.
The seventh chapter by H . B. White ZZZ summarizes the
present state of knowledge concerning biosynthesis, interconversion, degradation and excretion of pyridine nucleotides and their secondary metabolites. In the eighth chapter M . B. Grisham and J. Everse deal with the role of pyridine nucleotide oxidases in the formation of activated
oxygen species during phagocytosis.
Chapter 9 from the pens of R . R . Fisher and S . R. Earle,
summarizes the available information on membranebound transhydrogenases concerned with electron transport in microorganisms and mitochondria, including the
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problem of energy coupling. In the last chapter P. H . Pekala and B. M . Anderson discuss those reactions where
NAD is not a redox partner but a substrate: the mono- and
poly-ADP-ribosyl transfer to proteins. The former concerns, besides the NAD-glycohydrolases, above all the
chemical modification of regulatory proteins triggered off
by toxins (cholera, diphtheria, etc.);the latter processes occurs in the cell nucleus and seems to influence DNA repair
and DNA synthesis during differentiation and during the
cell cycle.
This well-produced book, which is provided with an index, can offer biochemists, biophysicists and cell biologists
new as well as established material in a clear and competently discussed form. Its up-to-date character recommends it to the teacher as well as to the advanced student
and the active research worker. The price may be high but
not inappropriate for what is offered.
Karl Decker [NB 599 IE]
Biochemisches Institut, Freiburg (FRG)
Electron Distributions and the Chemical Bond. Edited by P.
Coppens and M . B. Hall. Plenum Press, New York 1982.
ix, 419 pp., bound, $ 55.00
The Spring 1981 Meeting of the American Chemical Society held at Atlanta, GA, included a Symposium dealing
with Electron Distributions and the Chemical Bond. This
book is the written account of the lectures presented at the
Symposium. Its 21 chapters cover a wide range of topics
all concerned in one way or another with charge densities
in molecules or in extended solids as obtained either experimentally from X-ray diffraction measurements or theoretically from quantum-mechanical calculations. Both of
these approaches have made enormous advances over the
last decade or so, but each of them also has its own built-in
deficiencies. Fortunately, the errors and approximations
inherent in the one approach are virtually independent of
those in the other, and it is clearly in the confrontation between theory and experiment that the Editors of this book
expect its main interest to lie. As far as one can judge,
where high-quality comparisons are available for molecular systems containing only light atoms (say, up to F) the
results agree rather well. However, the confidence that
might be generated by such comparisons does not necessarily extend to studies of systems containing heavier
atoms which are much more difficult either to measure or
to compute reliably.
As with most books based on Conference proceedings,
the quality of the individual chapters is very uneven.
Among the more valuable contributions should be mentioned those of Smith (on theory), of Coppens (on the experimental approach, and including a useful glossary of
terms that should help newcomers to follow the jargon),
and of Breitenstein et al. (on comparison of experiment
and theory). The article by Zrngartinger gives a good idea
of what can be learned from careful experimental electrondensity studies of organic molecules. At the other end of
the scale, some of the contributions appear to be at best of
merely anecdotal interest. One article that can hardly fail
to raise a few eyebrows is that by Troup, Extine and Ziolo
on electron-density studies on tellurium compounds.
Doubtless some people will be impressed by their claim to
have obtained experimental evidence for bonding density
features such as lone pairs in heavy-atom systems, but
many others will find it difficult to see how the concluAnyew. Chem. Int. Ed. Enyl. 23 (1984) No. I
sions presented by these authors can possibly stand up to
critical scrutiny of the evidence. Presumably, the lecture itself provoked some lively discussion, and it seems perhaps
a pity that only one side of the story is presented in the
printed proceedings.
Several chapters mention the theorem due to Hohenberg
and Kohn, according to which all ground-state properties
of any system, including the wave function, are functionals
of the charge density distribution, i.e. they can be calculated in principle from a knowledge of the charge density.
The “in principle” is important, because nobody so far
seems to actually know how to calculate these functionals.
However, since the charge density is an observable while
the wave function is not, the Hohenberg-Kohn theorem
and its repercussions (discussed in the chapter by Parr)
may help to explain why interest among experimentalists
and theoreticians in charge-density studies of molecules
and extended systems is so lively. The publication of this
book is an expression of this interest. From it, the reader
can hope to find some of the questions that are being
asked in the area as well as some of the answers that are
being given.
Jack D . Dunitz [NB 603 IE]
Institut fur Organische
Chemie der ETH, Zurich
Covalent Catalysis by Enzymes. By L. B. Spector. SpringerVerlag, Berlin 1982, xii, 276 pp., bound, DM 78.00
Covalent enzymic catalysis (double displacement) has
been known for a long time. It is accepted as a guiding
principle, almost without exception, in the mode of action
of vitamins as enzyme cofactors, that the chemical process
of substrate reaction takes place on the vitamin unit. Some
of these cofactors are covalently bound to their apoenzyme ; knowledge of covalent enzymic catalysis stretches
back more than half a century.
In 1971 R . M . Bell and D . E . Koshland compiled a list of
60 enzymes where the application of critical criteria revealed a high likelihood of covalent catalysis. A little later
this figure was raised to 140 by L. B. Spector, and the much
more thorough-going claim was made that all enzyme catalysis proceeds oia covalent enzyme-substrate intermediates.
The present monograph is an attempt to strengthen this
concept.
It would have been a good idea to acquaint the reader
with the criteria for direct reaction between substrates (single displacement; kinetic sequential; stereochemical inversion of configuration) together with their alternatives (double displacement; kinetic ping-pong; stereochemical retention of configuration; exchange reactions in the absence of
the second substrate; isolation of an enzyme substrate
complex and demonstration of its kinetic competence).
There is only inconclusive kinetic evidence for single displacement without discernible stereochemical consequence. The author founds his assertion that all catalysis is
covalent thus : “Single displacement is purely speculative,
because no positive evidence in support of it exists. For the
documentation of this statement I can do no more than
refer the reader to the whole corpus of chemical literature
on the chemical mechanism of enzyme action.”
The experimenter is faced with a difficult problem in demonstrating direct interaction between the substrates; he
must exclude covalent catalysis by every possible test, of
Angew. Chem. Int. Ed. Engl. 23 (1984) No. 1
necessity this means negative results, thus completing a vicious circle. This, however, does not mean that single displacement reactions do not exist as this author so vehemently insists. Inversions of configuration which indicate
direct reaction of the substrates are craftily interpreted by
the author as triple displacements. This may be the case
but it has not been demonstrated. What is certain is that
the examples cited (acetate kinase, adenosine-phosphoribosyl transferase) are insufficient to lead to a conclusion.
It would have been a good idea to acquaint the reader
with examples that mimic covalent catalysis : exchange
reactions with a substrate may result from a second substrate being firmly attached to the enzyme; a substrate
alone may become covalently attached to the enzyme in a
side reaction; unphysiological substrate analogues (e. g.
suicide inhibitors) may form covalent enzyme substrate
bonds when the physiological substrate does not. Finally,
some isotope labeling experiments that purport to demonstrate covalent attachment can be attributed to faulty control experiments.
Conclusions that catalysis is covalent are only convincing when all the criteria are fulfilled or when a deviation
can be explained. It lies in the nature of a claim that all catalysis is covalent, that the author ignores this critical illumination and does not adequately distinguish experimental demonstration from experimental indications. It can be
left to the reader to check the significance of the results described and to decide whether he is reading “covalent catalysis above all” or “above all covalent catalysis”.
In this spirit it is possible to recommend this book,
which is deliberately provocative, lively and, on occasions,
informative, to everyone with an interest in the mechanism
of enzymic reactions.
Hermann Eggerer [NB 600 IE]
Physiologisch-ChemischesInstitut
der Technischen Universitat Munchen (FRG)
Methods in Stereochemical Analysis I. Stereochemical Applications of NMR Studies in Rigid Bicyclic Systems. By
A . P. Marchand, Verlag Chemie International, Deerfield
Beach 1982, 231 pp., bound, DM 280.00
This book is the first of a new series of monographs to
be edited by the author, which is to cover the application
of NMR, together with other spectroscopic and physical
methods, to stereochemical problems.
This first volume is devoted to the NMR spectroscopy of
the bicyclo[2.2.l]heptanes and the [2.2.2]octanes, which
have achieved great importance, not only as models for
spectroscopic investigation but also for preparative and
mechanistic studies, since these rigid molecules are particularly suitable for stereochemical studies.
The book is divided into three chapters. The first chapter presents methods of signal assignment and discusses
them in detail using examples. The chapter begins with a
study of the application of lanthanoid shift reagents in the
evaluatibn of ‘H-NMR spectra, where the theoretical
background is largely ignored; then the homo- and heteronuclear nuclear Overhauser effect (NOE) is introduced. A
word of criticism is pertinent at this point. Even though
this monograph does not aim to discuss measuring techniques, the enormous refinement of NMR techniques in
recent years makes it desirable to discuss assignment aids
somewhat more fully. This is particularly the case since it
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