Enzymes: Biochemistry, Biotechnology, Clinical Chemistry

431 Pages·2007·33.1 MB·English

by  Trevor Palmer, Philip L. Bonner

ENZYMES:
Biochemistry, Biotechnology and Clinical Chemistry
Second Edition

"Talking of education, people have now a-days" (said he) "got a
strange opinion that every thing should be taught by lectures. Now, I
cannot see that lectures can do so much good as reading the books
from which the lectures are taken. I know nothing that can be best
taught by lectures, except where experiments are to be shewn. You
may teach chymestry by lectures -
You might teach making of shoes
by lectures!"
James Boswell: Life of Samuel Johnson, 1766

ABOUT THE AUTHORS

Trevor Palmer was born in South Yorkshire and graduated from Cambridge
University in 1966 with an honours degree in biochemistry, being influenced
by (amongst others) Peter Sykes in organic chemistry and Malcolm Dixon in
enzymology. He then worked as a clinical biochemist at the Queen Elizabeth
Hospital for Children, linked to the Institute of Child Health, University of
London, obtaining a PhD for research into inherited disorders. From this
emerged the two main interests of his subsequent career, enzymology and
evolution, the latter stimulating a further interest in the long-term effects of
natural catastrophes. He moved to Nottingham Trent University (then Trent
Polytechnic) in 1974, initially as a lecturer in biochemistry, before becoming
Head of Department of Life Sciences (1987), Dean of the Faculty of Science
and Mathematics (1992), Senior Dean of the University (1998) and Pro
Vice-Chancellor for
Academic
Development
(2002),
returning
to
predominantly academic activity as Emeritus Professor in 2006. His books
include Understanding Enzymes (1981), Principles of Enzymology for
Technological Applications (1993), Controversy -
Catastrophism and
Evolution (1999) and Perilous Planet Earth (2003). His wife, Jan, teaches
psychology and sociology (and is currently a part-time PhD student at
Leicester University). Their son, James, is carrying out postdoctoral studies
as a Leverhulme Fellow at Nottingham University and their daughter,
Caroline, is researching for a PhD at Sheffield University.

Philip L. Bonner went to school in Coventry, West Midlands, before
graduating from the University of Sussex in 1978 with an honours degree in
biochemistry. He then worked as a research assistant at Glaxo plc on
Merseyside before leaving to take up a Research Assistant/Demonstrator
post at Trent Polytechnic, where he obtained a PhD for research concerning
enzymes
associated
with
seed
germination.
Several
postdoctoral
appointments followed, at Bristol, Lancaster and Central Lancashire
Universities, working on a variety of topics including relaxin, aspartate
kinase and phospholipase C, before he was appointed as Senior Lecturer at
Nottingham Trent University in 1991. There, he has maintained his research
interests in enzymology and analytical biochemistry, working on the role of
transglutaminase in plant/animal tissue and methods to isolate and
characterise post-translationally-modified MHC peptides. His first single-
author book, on protein purification, was published in 2007. His wife, Liz, is
a manager of an occupational therapist team in Nottingham and their
daughter, Francesca, is at junior school.

ENZYMES:
Biochemistry, Biotechnology and Clinical Chemistry
Second Edition

Trevor Palmer, BA, PhD, CBiol, FIBiol, FIBMS, FHEA
Emeritus Professor in Life Sciences
Nottingham Trent University

Philip L. Bonner, BSc, PhD
Senior Lecturer in Biochemistry
Nottingham Trent University

WP

WOODHEAD
PUBLISHING
~
~

Oxford
Cambridge
Philadelphia
New Delhi

For:
Caroline, Francesca, James, Jan and Liz

Published by Woodhead Publishing Limited,
80 High Street, Sawston, Cambridge CB22 3HJ, UK
www.woodheadpublishing.com

Woodhead Publishing, 1518 Walnut Street, Suite 1100, Philadelphia,
PA 19102-3406, USA

Woodhead Publishing India Private Limited, G-2, Vardaan House, 7/28 Ansari Road,
Daryaganj, New Delhi – 110002, India
www.woodheadpublishingindia.com

First edition published by Horwood Publishing Limited, 2001
Second edition published by Horwood Publishing Limited, 2007
Reprinted by Woodhead Publishing Limited, 2011

© T. Palmer and P.L. Bonner, 2007
The authors have asserted their moral rights

This book contains information obtained from authentic and highly regarded sources. Reprinted
material is quoted with permission, and sources are indicated. Reasonable efforts have been
made to publish reliable data and information, but the authors and the publisher cannot assume
responsibility for the validity of all materials. Neither the authors nor the publisher, nor anyone
else associated with this publication, shall be liable for any loss, damage or liability directly or
indirectly caused or alleged to be caused by this book.
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Trademark notice: Product or corporate names may be trademarks or registered trademarks, and
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British Library Cataloguing in Publication Data
A catalogue record for this book is available from the British Library

ISBN 978-1-904275-27-5

Printed by Lightning Source

Table of Contents

Authors' preface ............................................................................. xiv

Part 1 : Structure and function of enzymes

1 An introduction to enzymes
1.1 What are enzymes? ...................................................................................... 2
1.2 A brief history of enzymes .......................................................................... 2
1.3 The naming and classification of enzymes ................................................. 3
1.3 .1 Why classify enzymes? ................................................................... 3
1.3 .2 The Enzyme Commission's system of classification ....................... 4
1.3.3 The Enzyme Commission's recommendations on
nomenclature .................................................................................. 5
1.3.4 The six main classes of enzymes ..................................................... 6

Summary of Chapter 1 .................................................................................... 11
Further reading ................................................................................................ 11
Problems .......................................................................................................... 11

2 The structure of proteins
2.1 Introduction ............................................................................................... 14
2.2 Amino acids, the building blocks of proteins ............................................ 15
2.2.1 Structure and classification of amino acids ................................... 15
2.2.2 Stereochemistry of amino acids ..................................................... 17
2.3 The basis of protein structure .................................................................... 18
2.3.1 Levels of protein structure ............................................................. 18
2.3.2 Bonds involved in the maintenance of protein structure ................ 19
2.4 The determination of primary structure ..................................................... 21
2.4.1 The isolation of each polypeptide chain ......................................... 21
2.4.2 Determination of the amino acid composition of
each polypeptide chain ................................................................ 24
2.4.3 Determination of the amino acid sequence of
each polypeptide chain ................................................................ 26
2.4.4 Determination of the positions of disulphide bridges ................... 29
2.4.5 Some results of experimental investigation of primary
structure .......................................................................................... .29
2.4.6 Indirect determination of primary structure ........................... 30

2.5 The determination of protein structure by X-ray crystallography ............ .30

2.5.1 The principles of X-ray crystallography ................................. 30
2.5.2 Some results of X-ray crystallography ............................................ 35
2.6 The investigation of protein structure in solution ............................... .40

vi
Table of Contents

Summary of Chapter 2 .................................................................. 42
Further reading ........................................................................... 42
Problems ................................................................................. 43

3 The biosynthesis and properties of proteins
3 .1 The biosynthesis of proteins ...................................................... .44
3.1.1 The central dogma of molecular genetics .................................. .44
3.1.2 The double-helix structure of DNA ....................................... .46
3 .1.3 The translation of genetic information into protein structure ......... .48
3.1.4 Modification of protein structure after translation ....................... 51
3.1.5 Control of protein synthesis ............................................... .52
3.1.6 Sequence determination ................................................... .55
3.2 The properties of proteins ............................................................ 57
3.2.1 Chemical properties of proteins ......................................... .57
3.2.2 Acid-base properties of proteins ......................................... 58
3.2.3 The solubility of globular proteins ....................................... 62
Summary of Chapter 3 .................................................................. 64
Further reading .......................................................................... 64
Problems .................................................................................. 65

4 Specificity of enzyme action
4.1 Types of specificity .................................................................. 67
4.2 The active site ........................................................................ 68
4.3 The Fischer 'lock-and-key' hypothesis .......................................... 70
4.4 The Koshland 'induced-fit' hypothesis ........................................... 70
4.5 Hypotheses involving strain or transition-state stabilization ................... 72
4.6 Further comments on specificity .................................................... 73
Summary of Chapter 4 ................................................................... 74
Further reading ............................................................................. 75

5 Monomeric and oligomeric enzymes
5.1 Monomeric enzymes ................................................................. 76
5.1.1 Introduction .................................................................. 76
5.1.2 The serine proteases ........................................................ 76
5.1.3 Some other monomeric enzymes .......................................... 78
5.2 Oligomeric enzymes ................................................................. 79
5.2.1 Introduction .................................................................. 79
5.2.2 Lactate dehydrogenase ..................................................... 79
5.2.3 Lactose synthase ............................................................. 81
5.2.4 Tryptophan synthase ......................................................... 81
5.2.5 The pyruvate dehydrogenase multienzyme complex .................. 82
Summary of Chapter 5 .................................................................. 83
Further reading ........................................................................... 83

Table of Contents
vii

Part 2 : Kinetic and chemical mechanisms of enzyme-catalysed reactions

6 An introduction to bioenergetics, catalysis and kinetics
6.1 Some concepts ofbioenergetics ................................................... 85
6.1.1 The first and second laws of thermodynamics ......................... 85
6.1.2 Enthalpy, entropy and free energy ....................................... 85
6.1.3 Free energy and chemical reactions ..................................... 86
6.1.4 Standard free energy ....................................................... 87
6.1.5 Bioenergetics and the living cell ......................................... 88
6.2 Factors affecting the rates of chemical reactions ............................... 89
6.2.1 The collision theory ....................................................... 89
6.2.2 Activation energy and the transition-state theory ..................... 89
6.2.3 Catalysis ..................................................................... 92
6.3 Kinetics ofuncatalysed chemical reactions ..................................... 93
6.3.l The Law of Mass Action and the order ofreaction .................... 93
6.3.2 The use of initial velocity ................................................ 95
6.4 Kinetics of enzyme-catalysed reactions: an historical introduction ......... 96
6.5 Methods used for investigating the kinetics of enzyme-catalysed
reactions ............................................................................. 98
6.5.1 Initial velocity studies ...................................................... 98
6.5.2 Rapid-reaction techniques ............................................... 100

6.6 The nature of enzyme catalysis .................................................. 100
Summary of Chapter 6 .................................................................. 102
Further reading ......................................................................... 102
Problems ................................................................................. 102

7 Kinetics of single-substrate enzyme-catalysed reactions
7 .1 The relationship between initial velocity and substrate
concentration ..................................................................... 105
7.1.1 The Henri and Michaelis-Menten equations .......................... 105
7.1.2 The Briggs-Haldane modification of the Michaelis-Menten
equation .................................................................... 107

7.1.3 The significance of the Michaelis-Menten equation ................. 109
7 .1.4 The Lineweaver-Burk plot .............................................. 111
7.1.5 The Eadie-Hofstee and Hanes plots ................................... 112
7.1.6 The Eisenthal and Comish-Bowden plot .............................. 114
7.1.7 The Haldane relationship for reversible reactions .................... 115
7 .2 Rapid-reaction kinetics ...................................................... 116
7.2.1 Pre-steady-state kinetics ................................................. 116
7.2.2 Relaxation kinetics ....................................................... 120

7.3 The King and Altman procedure ................................................. 121
Sunimary of Chapter 7 ................................................................. 124
Further reading ......................................................................... 124
Problems ................................................................................ 125

viii
Table of Contents

8 Enzyme inhibition
8.1 Introduction ...................................................................... 126
8.2 Reversible inhibition ............................................................. 126
8.2.1 Competitive inhibition .................................................. 126
8.2.2 Uncompetitive inhibition ............................................... 133
8.2.3 Non-competitive inhibition .............................................. 136
8.2.4 Mixed inhibition .......................................................... 140
8.2.5 Partial inhibition ......................................................... 143
8.2.6 Substrate inhibition ...................................................... 144
8.2.7 Allosteric inhibition ...................................................... 146
8.3 Irreversible inhibition ............................................................ 147
Summary of Chapter 8 ................................................................ 149
Further reading ........................................................................ 150
Problems ................................................................................ 150

9 Kinetics of multi-substrate enzyme-catalysed reactions
9.1 Examples of possible mechanisms ............................................. 153
9.1.1 Introduction ............................................................... 153
9 .1.2 Ping-pong bi-bi mechanism ............................................ 153
9.1.3 Random-order mechanism .............................................. 154
9.1.4 Compulsory-order mechanism ......................................... 154
9.2 Steady-state kinetics ............................................................. 155
9.2.1 The general rate equation of Alberty .................................. 155
9.2.2 Plots for mechanisms which follow the general rate
equation ................................................................. 157
9.2.3 The general rate equation of Dalziel ................................... 158
9.2.4 Rate constants and the constants of Alberty and Dalziel ........... 158
9 .3 Investigation of reaction mechanisms using steady-state methods ........ 160

9.3.1 The use of primary plots ................................................ 160
9 .3 .2 The use of inhibitors which compete with substrates
for binding sites ........................................................ 161
9.4 Investigation of reaction mechanisms using non-steady-state
methods .......................................................................... 165
9.4.1 Isotope exchange at equilibrium ....................................... 165
9.4.2 Rapid-reaction studies ................................................... 167
Summary of Chapter 9 ......................................................... 168
Further reading ......................................................................... 168
Problems ............................................................................... 168

10 The investigation of active site structure

10.1 The identification of binding sites and catalytic sites ...................... 173

10.1.l Trapping the enzyme-substrate complex ........................... 173
10.1.2 The use of substrate analogues ....................................... 17 4
10.1.3 Enzyme modification by chemical procedures affecting
amino acid side chains ................................................ 175

Table of Contents
ix

10.1.4 Enzyme modification by treatment with proteases .............................. 179
10.1.5 Enzyme modification by site-directed mutagenesis .............. 179
10.1.6 The effect of changing pH ........................................... 180
10.2 The investigation of the three-dimensional structures of
active sites ..................................................................... 185

Summary of Chapter 10 .................................................................. 187
Further reading ........................................................................ 187
Problem ................................................................................ 188

11 The chemical nature of enzyme catalysis
11.1 An introduction to reaction mechanisms in organic chemistry ........... 189
11.2 Mechanisms of catalysis ....................................................... 191
11.2.1 Acid-base catalysis .................................................... 191
11.2.2 Electrostatic catalysis ................................................ 192
11.2.3 Covalent catalysis ..................................................... 192
11.2.4 Enzyme catalysis ...................................................... 193
11.3 Mechanisms of reactions catalysed by enzymes without cofactors ...... 194
11.3.1 Introduction ............................................................ 194
11.3.2 Chymotrypsin .......................................................... 194
11.3.3 Ribonuclease .......................................................... 195
11.3.4 Lysozyme ............................................................... 196
11.3.5 Triose phosphate isomerase .......................................... 199
11.4 Metal-activated enzymes and metalloenzymes .............................. 200

11.4.1 Introduction ............................................................ 200
11.4.2 Activation by alkali metal cations (Na+ and K+) .................. 200
11.4.3 Activation by alkaline earth metal cations
(Ca2+ and Mg2l .................................................... 201

11.4.4 Activation by transition metal cations (Cu, Zn, Mo, Fe
and Co cations) ...................................................... 202

11.5 The involvement of coenzymes in enzyme-catalysed reactions .......... 204

11.5.1 Introduction ............................................................ 204
11.5.2 Nicotinamide nucleotides (NAD+ and NADPl ................... 205
11.5.3 Flavin nucleotides (FMN and FAD) ................................ 207
11.5.4 Adenosine phosphates (ATP, ADP and AMP) ................... 210
11.5.5 Coenzyme A (CoA.SH) ............................................. 211
11.5.6 Thiamine pyrophosphate (TPP) ..................................... 212
11.5. 7 Pyridoxal phosphate .................................................. 214
11.5.8 Biotin .................................................................... 216
11.5.9 Tetrahydrofolate ....................................................... 217
11.5.10 Coenzyme B12 ......................................................... 218

Summary of Chapter 11 .............................................................. 220
Further reading ......................................................................... 220

12 The binding of ligands to proteins
12.1 Introduction ...................................................................... 222

x
Table of Contents

12.2 The binding of a ligand to a protein having a single ligand-binding
site .................................................................................. 222
12.3 Cooperativity .................................................................... 223
12.4 Positive homotropic cooperativity and the Hill equation .................. 224
12.5 The Adair equation for the binding of a ligand to a protein
having two binding sites for that ligand ................................... 227
12.5.1 General considerations ............................................... 227
12.5.2 Where there is no interaction between the binding sites ........ 228
12.5.3 Where there is positive homotropic cooperativity .............. 230
12.5.4 Where there is negative homotropic cooperativity .............. 230

12.6 The Adair equation for the binding of a ligand to a protein
having three binding sites for that ligand .................................. 231
12. 7 The Adair equation for the binding of a ligand to a protein
having four binding sites for that ligand .................................... 232
12.8 Investigation of cooperative effects .......................................... 232
12.8.1 Measurement of the relationship between Y and (S] ............ 232
12.8.2 Measurement of the relationship between v0 and [So] ............ 233
12.8.3 The Scatchard plot and equilibrium dialysis techniques ........ 233
12.9 The binding ofoxygen to haemoglobin ..................................... 236
SummaryofChapter 12 ............................................................. 237
Further reading ......................................................................... 237
Problems ................................................................................ 238

13 Sigmoidal kinetics and allosteric enzymes
13 .1 Introduction ....................................................................... 23 9
13 .2 The Monod-Wyman-Changeux (MWC) model ............................ 239
13.2.1 The MWC equation .................................................. 239
13.2.2 How the MWC model accounts for cooperative effects ......... 242
13.2.3 The MWC model and allosteric regulation ....................... 242
13.2.4 The MWC model and the Hill equation ........................... 244
13.3 The Koshland-Nemethy-Filmer (KNF) model .............................. 245
13.3.1 The KNF model for a dimeric protein ............................. 245
13.3.2 The KNF model for any oligomeric enzyme ..................... 247
13 .3 .3 The KNF model and allosteric regulation ......................... 248
13 .4 Differentiation between models for cooperative binding
in proteins ...................................................................... 248
13.5 Sigmoidal kinetics in the absence of cooperative binding ................ 249
13.5.1 Ligand-binding evidence versus kinetic evidence ................ 249
13.5.2 The Ferdinand mechanism ........................................... 250
13.5.3 The Rabin and mnemonical mechanisms .......................... 250

Summary of Chapter 13 .............................................................. 251
Further reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..... 251
Problems ............................................................................... 252

Table of Contents
xi

14 The significance of sigmoidal behaviour
14.1 The physiological importance of cooperative oxygen-binding
by haemoglobin ............................................................... 255
14.2 Allosteric enzymes and metabolic regulation ................................ 257
14.2.1 Introduction ............................................................ 257
14.2.2 Characteristics of steady-state metabolic pathways ............... 258
14.2.3 Regulation of steady-state metabolic pathways by
control of enzyme activity ........................................ 260

14.2.4 Allosteric enzymes and the amplification of metabolic
regulation ............................................................. 262
14.2.5 Other mechanisms of metabolic regulation ........................ 263
14.2.6 Some examples of allosteric enzymes involved in
metabolic regulation ................................................ 268
Summary of Chapter 14 ............................................................ 271
Further reading ....................................................................... 272

Part 3: Application of enzymology

15 Investigation of enzymes in biological preparations
15 .1 Choice of preparation for the investigation of enzyme
characteristics ................................................................. 274
15.2 Enzyme assay ................................................................... 276
15.2.l Introduction ............................................................ 276
15 .2.2 Enzyme assay by kinetic determination of catalytic
activity ............................................................... 277
15.2.3 Coupled kinetic assays ............................................... 280
15.2.4 Radioimmunoassay (RIA) of enzymes ............................. 282
15 .3 Investigation of sub-cellular compartmentation of enzymes .............. 284
15. 3 .1 Enzyme histochemistry ............................................... 2 84
15 .3 .2 The use of centrifugation ............................................. 286
15.3.3 Some results of the investigation of enzyme
compartmentation .................................................. 289
Summary of Chapter 15 .................................................................. 291
Further reading ...................................................................... 291
Problem ................................................................................ 292

16 Extraction and purification of enzymes
16.1 Extraction of enzymes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. .. 293
16.1.1 Introduction ...................................................
...293
16.1.2 The extraction of soluble enzymes . . .. . . . . . . . . . .. . . . . . . . . .
. .. 293
16.1.3 The extraction of membrane-bound enzymes ............
. .. 294
16.1.4 The nature of the extraction medium ........................ . .. 297
16.2 Purification of enzymes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . .
. .. 298
16.2.1 Preliminary purification procedures .............................. 298
16.2.2 Further purification procedures .................................... 299
16.2.3 Criteria of purity ..................................................... 307

xii
Table of Contents

16.3 Determination of molecular weights of enzymes ................................ .311

Summary of Chapter 16 .............................................................. 312
Furtherreading ........................................................................ 313
Problem ............................................................................... .314

17 Enzymes as analytical reagents
17 .1 The value of enzymes as analytical reagents ................................. 315
17 .2 Principles of enzymatic analysis .............................................. 316
17.2.l End-point methods ................................................... 316
17.2.2 Kinetic methods ...................................................... 319
17.2.3 Immunoassay methods ............................................. 323
17.3 Handling enzymes and coenzymes ......................................... 324
Summary of Chapter 17 ............................................................ .326
Further reading ...................................................................... .326
Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. .. .327

18 Instrumental techniques available for use in enzymatic analysis
18.1 Principles of the available detection techniques .......................... .328
18.1.1 Introduction ........................................................... 328
18.1.2 Manometry ............................................................ 328
18.1.3 Spectrophotometry ................................................... 329
18.1.4 Spectrofluorimetry ................................................... 330
18.1.5 Electrochemical methods ........................................... 331
18.1.6 Enthalpimetry ......................................................... 334
18.1. 7 Radiochemical methods ............................................. 334
18.1.8 Dry-reagent techniques .............................................. 335
18.2 Automation in enzymatic analysis ............................................ 336
18.2.1 Introduction .......................................................... 336
18.2.2 Fixed-time methods ................................................... 33 7
18.2.3 Fixed-concentration methods ....................................... 339
18.2.4 Methods involving continuous monitoring ........................ 340

18.3 High-throughput assays (HTA) ............................................... 341
Summary of Chapter 18 ............................................................. 342
Further reading ........................................................................ 342

19 Applications of enzymatic analysis in medicine, forensic science
and industry
19.1 Applications in medicine ....................................................... 343
19 .1.1 Assay of plasma enzymes ............................................ 343
19 .1.2 Enzymes and inborn errors of metabolism ....................... 348
19.1.3 Enzymes as reagents in clinical chemistry ........................ 352
19.2 Applications in forensic science .............................................. 352
19.3 Applications in industry ....................................................... 353
Summary of Chapter 19 .............................................................. 355
Further reading ....................................................................... 355

Table of Contents
Xlll

20 Biotechnological applications of enzymes

20.1 Large-scale production and purification of enzymes ....................... 356

20.1.1 Production of enzymes on an industrial scale .................... 356
20.1.2 Large-scale purification of enzymes ............................... 359
20.1.3 Synthesis of artificial enzymes ..................................... 360
20.2 Immobilized enzymes .......................................................... 361

20.2.1 Preparation of immobilized enzymes .............................. 361
20.2.2 Properties of immobilized enzymes ................................ 366
20.2.3 Applications of immobilized enzymes:
general principles ...................................................... .368

20.3 Enzyme utilization in industry ................................................ 369

20.3.1 Introduction ........................................................... 369
20.3.2 Applications in food and drink industries ......................... 370
20.3.3 Applications in other industries ..................................... 373
Summary of chapter 20 ............................................................. 374
Further reading ....................................................................... 374
Problems ............................................................................... 376

21 Genomics, proteomics and bioinformatics
21.1 Enzymes and recombinant DNA technology ................................ 377
21.1.1 Introduction ........................................................... 3 77
21.1.2 Applications .......................................................... 378
21.2 Proteomics ....................................................................... 387
21.2.1 The application of mass spectrometry to the investigation
of the proteome ........................................................ 387
21.2.2 Proteomics research .................................................. 389
21.3 Enzymes and bioinformatics ................................................. 390

21.3.l Introduction .......................................................... 390
21.3.2 Systems biology and microarrays .................................. 392
Summary of Chapter 21 ............................................................ 393
Further reading ....................................................................... 393
Problems ............................................................................... 396

Answers to problems ........................................................................ 397

Abbreviations .............................................................................. 403

Index .......................................................................................... 405

Authors' Preface

This book was written, as all textbooks should be, with the requirements of the
student firmly in mind. It is intended to provide an informative introduction to
enzymology, and to give a balanced, reasonably-detailed, account of all the various
theoretical and applied aspects of the subject which are likely to be included in an
honours degree course. Furthermore, some of the later chapters may serve as a
bridge to more advanced texts for students wishing to proceed further in this area of
biochemistry.
Although the book is intended mainly for students taking first degree courses
which have a substantial biochemistry component, large portions may be of value to
students on comparable courses in biological sciences, biomedical sciences or
forensic sciences, and even to ones emolled on, in one direction, foundation
programmes, or, in the other, MSc or other advanced courses who are approaching
the subject of enzymology for the first time (or the first time in many years).
No previous knowledge of biochemistry, and little of chemistry, is assumed.
Most scientific terms are defined and placed in context when they are first
introduced. Enzymology inevitably involves a certain amount of elementary
mathematics, and some of the equations which are derived may appear somewhat
complicated at first sight; however, once the initial biochemical assumptions have
been understood, the derivations usually follow on the basis of simple logic, without
involving any difficult mathematical manipulations. Numerical and other problems
(with answers) are included, to test and reinforce the student's grasp of certain
points. These problems generally use hypothetical data, although the results are
often based on findings reported in the biochemical literature.
If the size of the book is to be kept reasonable, some things of value have to be
left out. The chief aim of this particular book is to help the student understand the
concepts involved in enzymology, and the historical context in which they were
worked out. It is not a reference book for practising enzymologists, so no
comprehensive tables of data or long, finely-detailed accounts are included. Instead,
an attempt has been made to give a perspective of each topic, and examples are
quoted where appropriate. Credit has been given wherever possible to those
responsible for the development of the subject, but many names deserving of
mention have been excluded for reasons of space.