Oxford Dictionary of Biochemistry and Molecular Biology

753 Pages·2000·13.22 MB·English

by  Anthony Smith

OXFORDDICTIONARYOF
BIOCHEMISTRY
AND
MOLECULAR BIOLOGY
Editors
General Editors Subject Editors
DrA. D. Smith(ManagingEditor) EmeritusReaderin DrD. A. Bender SeniorLecturer, Departmentof
Biochemistry,andHonoraryResearchFellow, Department BiochemistryandMolecularBiology, University College
ofMolecularPathology, University CollegeLondonMedical London
School DrA. J. Carozzi NHandMRCResearchOfficer, Centrefor
ProfessorS.P. Datta EmeritusProfessorofMedical MolecularandCellularBiology, UniversityofQueensland
Biochemistry,andHonorary ResearchFellow, Department ProfessorT.W. GoodwinFRS EmeritusJohnson Professor
ofBiochemistryandMolecularBiology, University College ofBiochemistry, UniversityofLiverpool
London
DrJ. H. Parish SeniorLecturer,SchoolofBiochemistryand
DrG. HowardSmith HonoraryResearch Fellow, MolecularBiology, UniversityofLeeds
DepartmentofBiochemistryandMolecular Biology,
DrS. C. Stanford SeniorLecturer, Departmentof
University CollegeLondon
Pharmacology, University College London
ProfessorP. N. Campbell EmeritusProfessorof
Biochemistry,andHonoraryResearchFellow, Department
ofBiochemistryandMolecularBiology, University College
London
ProfessorR. Bentley ProfessorEmeritusofBiochemistry,
DepartmentofBiologicalSciences, UniversityofPittsburgh
DrH. A. McKenzie Fellow, SchoolofChemistry, University
ofNew South Wales, AustralianDefenceForceAcademy,
and Visitor, MolecularMedicine, John CurtinSchoolof
MedicalResearch, TheAustralianNational University,
Canberra
OXFORD DICTIONARY OF
BIOCHEMISTRY
AND
MOLECULAR BIOLOGY
REVISED EDITION
ManagingEditor DrADSmith UniversityCollegeLondon
GeneralEditors ProfessorSPDatta UniversityCollegeLondon
DrGHSmith UniversityCollegeLondon
ProfessorPNCampbell(Chairman) UniversityCollegeLondon
DrRBentley UniversityofPittsburgh
DrHAMcKenzie AustralianDefenceForceAc.
SubjectEditors DrDABender UniversityCollegeLondon
DrAJHarris UniversityofQueensland
ProfessorTWGoodwin UniversityofLiverpool
DrHAMcKenzie AustralianDefenceForceAc.
DrJHParish UniversityofLeeds
DrCStanford UniversityCollegeLondon
OXFORD
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Preface
Nearly twenty years ago one ofus (S. P. D., soonjoined by Molecular biology is a closely related discipline that origi
G. H. S.),beganadistillationoftheelementsofbiochemistry nates in the study ofDNAanditsmetabolism, and now em
into an alphabetical arrangement. The task was formidable bracesallthoseinvestigationsthatexploitthetechnologythat
andeventuallyothereditorswererecruited,aneditorialboard has resulted from this work. Both disciplines aim to explain
was established, and now the work is offered as the Oxford the behaviour of life-forms in molecular terms, and are so
DictionaryofBiochemistryandMolecular Biology.Itishoped closely interrelated that separationis barely possible. Itisin
that the dictionary will serve the needs of the research bio evitablethatthecontentofthisdictionaryisto adegreearbi
chemistormolecular biologist, aswell asteachersofthesub trary, but it is hoped that all important aspects of these
jectandtheirstudents.Inaddition,itshouldproveofvalueto subjects have received consideration. The compilers have at
practitioners of other fields of study or work seeking the temptedtoofferabroadcoverageoftermsencounteredinthe
meaningofabiochemicalterm. literatureofbiochemistryandmolecularbiologybyincluding
An important function ofa dictionary is to provide guid an appreciable number from cognate sciences. Although the
ance oncurrentusage in the field withinitsscope. The origi compilationisdesignedprimarilytoservereaders ofcontem
nal 12-volume OxfordEnglish Dictionary wascompiled from porary material, the needs ofthose who tum to older litera
aboutfive millionslipsofpaperbearingsentencesorphrases ture have also been borne in mind. Some ofthe entries thus
extractedbysomethousandsof'readers'fromclassicalworks have a historical flavour, some obsolete terms are included
ofliterature and those ofthe best contemporary authors. It (e.g. zymase), and in some cases a historical approach has
was thus firmly based on good usage. In scientific subjects, beenusedasthebestmeansofpresentinganexplanationofa
specialistterminologyisoftencodifiedinsetsofrecommenda term, as for example in the case ofthe entry for gene. The
tions regarding nomenclature, meaning, abbreviations, sym value of a scientific dictionary is enhanced by inclusion of
bols, and so on. These have been agreed by international contextualinformationaswellasmereexplanationsofmean
commissions (e.g. those ofThe International Union ofPure ing or terminology. This dictionary will be found to have
andAppliedChemistryand TheInternational UnionofBio someoftheattributesofanencyclopedia,althoughtheextent
chemistry and Molecular Biology) as a means ofpreserving towhichitveersinthisdirectionhasvariedwiththewhimof
order and facilitating communication between scientists. We itscompilers.Itisourhopethatinasinglevolumethereader
have striven to conform as far as possible to the relevant in haseasyaccesstobasicdefinitionsaswellasageneroushelp
ternationalrecommendations,butinsomecases,whereusage ingofotherinformation.
sofrequentlydivergesfromarecommendationthatadherence In the present-day world, we are assailed by floods of
to it would seriously detract from ease ofuse ofthe diction 'information'.Ithasbeensuggestedthattheaverageweekday
ary, wehavekept to theprinciple that the dictionaryshould edition ofa newspaper ofrecord (e.g. The New York Times)
reflect usage (see the definitions oflexicographer). This does providesmoreinformationthanShakespeareandhiscontem
not extend, ofcourse, to cases where usage, however wide porarieswouldhaveacquiredinalifetime.Withtheavailabil
spread, contradicts sound scientific principles. The interna ityofmuchinformationthroughtheInternet,itmaybeasked
tionally agreed recommendation is always also listed. The whether a dictionary in paper form is actually necessary. In
various compilations of these recommendations that have answer,wenotethattheInternetcanbeslow,andisnotread
been drawn upon are listed in Appendix B, together with a ilyaccessibleinsomepartsoftheworld;thedatabasesmaybe
numberofothersourcesofinformationonnomenclature. inadequate, and although usually very up-to-date, the high
Biochemistry is the discipline that embraces the study of costoftheirmaintenance restricts themtospecializedknowl
thestructureandfunction oflife-formsatthemolecularlevel. edge in a limited number offields. Moreover, books have a
vi
Preface
qualityoftheirown,whichisenablingthemtomaintaintheir We are pleased to acknowledge the collaboration and
popularity.ItappearsthattheincreasinguseoftheInternetis materialsupportgiven tous byOxford UniversityPress. We
actually paralleled by the rate ofpublication ofprinted dic also acknowledge the very friendly cooperation of Market
tionaries; in an information-hungry age, there cannot be too House Books, especially the patience and good humour of
manysourcesofgood-qualityinformation. Dr John Daintith through all the complications ofthe pro
We are deeply indebted to the Leverhulme Trust for the duction.Thecopyeditors,RobertHineandJaneCavell,made
award ofan emeritus fellowship to one ofus (A. D. S.), to anumberofhelpfulsuggestions.
University College London, which has provided us with Thecompilersofferno apologyfor theirfailure to include
friends and expertcolleagues, and to DrO. Theodor Benfey, manydeservingtermsinthedictionary, butwouldbepleased
DrMaryEllenBowden,andProfessorArnoldThackray,The to havetheirattentiondrawntoerrorsandto receivesugges
BeckmanCenterforHistoryofChemistry,ChemicalHeritage tionsforadditionalentriesinanyfutureedition.
Foundation,Philadelphia,andDrJohnEdsall,HarvardUni Correspondence concerning the dictionary is best ad
versityfor assistancewithbiographicaldata. dressed to the Managing Editor, Oxford Dictionary ofBio
Particularthanks are due to Dr H. B. F. Dixon for much chemistryandMolecularBiology,c/oOxfordUniversityPress,
advice on nomenclature and related matters. Help on ques GreatClarendonStreet,OxfordOX26DP
tionsofnomenclaturefromDrG. P.MossandDrA. D. Mc
Naught is also acknowledged. We are grateful to Dr D. H.
January 1997 A. D. Smith
JenkinsonforhishelpwiththerecommendationsoftheInter
S.P.Datta
national Committee on Nomenclature in Pharmacology. We
G. H. Smith
are also grateful for the valuable advice ofProfessor K. W.
P. N. Campbell
Taylorand DrJ. L. Crammer, onclinicaltopics, andProfes
R.Bentley
sor M. C. W. Evans, onplant biochemistry, and to DrMar
H.A. McKenzie
garetMcKenzie,forreadingtheproofs.
Duringtheearlierstagesoftheproject, MrsS. Govegave
Thiswholebookisbutadraught-nay, butthedraughtof
muchvaluableassistanceand MissA. Strakerwasmosthelp
adraught. Oh, Time, Strength, Cash, andPatience.
fulinsuggestingtermsforinclusion.Wealsowishtothankall
those other friends and colleagues, in addition to those sep HermanMelville(1851)MobyDick, orThe Whale
aratelylisted,whohaveunstintinglygivenushelpandadvice. (ed.T.Tanner, 1988,p. 147,OxfordUniversityPress).
Preface to the revised edition
It must be inevitable with any work of this nature that a deleted. In addition, Appendices B, C, and D have been
numberofimperfectionsanderrorsoccur.Sotheopportunity updated, and Appendix B has been expanded and provided
providedbytheneedtoreprintthisdictionaryhasbeentaken withalltherelevantInternetaddressesavailableatthetimeof
toeffectsomeimprovementswithinthelimitationimposedby writing.
retention oftheoriginalpagination. Aswellasthecorrection Valuable comments on the original edition by a number of
ofavarietyofminormisprintsandotherminordefects, over readers are gratefully acknowledged, and thanks are again
four hundredentriesbeeneitherrevisedorcompletelyrewrit due to Dr. H. B. F. Dixon for advice on aspects ofnomen
ten, and fifty or so new entries have been provided, some to clature as well as to Oxford University Press and Market
remedy deficiencies and others to provide additional terms HouseBooksfor theirmuchappreciatedcooperation.
that have become oftopical interest. To help make way for
the new ones, about halfas many original entries have been September1999 A. D. S.
Note on proprietary status
Thisdictionaryincludessomewordswhichare, orare asserted to be, proprietarynamesortrademarks. Theirinclusiondoes
notimplythattheyhaveacquiredforlegalpurposesanon-proprietaryorgeneralsignificance, norisanyotherjudgementim
pliedconcerningtheir legalstatus. Incaseswhere the editor has someevidence that a word is used as a proprietaryname or
trademarkthisisindicatedbythedesignationproprietaryname,butnojudgementconcerningthelegalstatusofsuchwordsis
madeorimpliedthereby.
Guide to the Dictionary
1. Alphabetical order 1.4 Secondary order involving locants
When such modifiers constitute the only difference between
1.1 Main order of headwords
two headwords, they determine the alphabetical order ofthe
Alphabetical order is determined on a letter-by-letter basis, entries:
notwordbyword;spacesaredisregarded: benzodiazepine encephalitis
acid o-benzoquinone 3'-end
p-benzoquinone 5'-end
acidanhydride
benzoyl end+
acid-base balance
acid-basecatalysis
1.5 Format differences in headwords
acid dissociation constant
The order for entries where the headword is identical except
acid dye
forformat is
acidemia
b, b, b-, b-,-b,-b, B, B, B-, 8-,-B,-B
1.2 Nonalphabetic characters
1.6 Subscripts and superscripts
Numbers, hyphens, primes,andsubscript/superscripttextare
Single letters with subscripts or superscripts are treated as
ignoredforthepurposeofindexing;anexampleisthefollow
single letters for the purposes ofindexing, soentries for k
ingsequenceofentries: eet
and K will both be found in the list ofsingle-letter entries
m
FSH·RH at the beginning ofthe letter K. The primary order ofthese
F1 sphere single-letterentries isdetermined by theirformat (see section
F'strain 1.5); where there is more than oneentry with a given format
F-type penton phosphate pathway (e.g. italic, lowercase k), these are arranged by alphabetical
ftz orderoftheirsubscripts/superscripts.
1.3 Locants and modifiers 1.7 Greek letters
• Where Greek letters form part ofa chemical name, they
In chemicalnames, any locants and otherhyphenated modi
are not used to determine alphabetical order (see section
fiers such as cis-, trans-,PO, and alphabetic Greek characters
1.3).Otherwisetheyarewrittenoutinfullintheheadword,
are not used to determine primary alphabetical order; hence
e.g. nu body, beta strand.
thefollowingentriesallappearundertheletterA:
• The names ofthe letters ofthe Greek alphabet, together
N-acetylgalactosamine
withtheirEnglishtransliterationsusedinetymologies,are
p-aminobenzoicacid listed in Appendix A. The meanings assigned to Greek
y-aminobutyrateshunt alphabetic characters used as symbols are also given in
6-aminohexanoicacid AppendixA.
However, the unhyphenated letters 'c' in 'cDNA' and 'd' in • Greek characters are set in italic type when the character
'dCTP',for example, aretreatedasintegralpartsoftheword represents a variable orlocant and in roman type when it
andareusedtodeterminealphabeticalorder. representsaunitorsubtypee.g.ofaproteinorparticle.
viii
GuidetotheDictionary
2. Format of entries bilirubin or (formerly) bilirubin IXa the recommended
trivialnamefor the linear tetrapyrrole....
2.1 Summary of typefaces • Thesealternativetermsandspellingsalsoappearasentries
• Thefollowingdistinguishingtypefacesareemployedinad in the alphabetical sequence, with a cross-reference to the
main entry where the term is defined, unless the variant
ditiontothetextlightseriftypefaceusedfordefinitions:
wouldappearcloseto themainentry. Additionalinforma
large boldsansserif headwords
tionisgivenwhereappropriate:
textboldserif alternative terms for and vari
demoxytocin an alternativenamefor deaminooxytocin.
antspellingsofheadwords;hid
fructose-1,6-diphosphatase a former name for fruc
denentries;run-ons tose-bisphosphatase.
textboldsansserif cross-references lipideavariantspellingoflipid.
textitalicserif usage notes and field labels; molecularexclusionchromatographyalesscommon
parts of speech; foreign lan namefor gel-permeationchromatography.
guage terms (including scien oleomargarine an alternative name (esp. US) for mar
tific and medical Latin); garine.
symbols for physical quantities penatinan obsoletenamefor glucoseoxidase.
and fundamental physical con
2.3.3Chemicalnames
stants; stereochemical prefixes
• Synonyms may be given following the headword, in the
andalphabeticallocants
order: other trivial names (ifany); the semi-systematic or
semi-trivial name(s); older systematicname instyle, ifstill
2.2 Headwords
inwidespreaduse;thesystematicnameincurrentlyrecom
• Foreachentry,theheadwordisinbold,sansseriftype.
mendedstyle.
• Upper-case(capital)initiallettersareusedonlyforproper
• Theheadwordusedtorepresentachemicalcompoundthat
names (or terms derived from them) and for proprietary
canexistinionizedform(s) isinmostcasesthenameofits
names. Abbreviations and symbols are printed in upper
physiologically predominant form. So, for example, an
and/orlowercaseasappropriate.
entryisheaded'succinate'ratherthat'succinicacid'.
• Ifa term would normally be set in bold type, this is indi
catedintheentry: 2.3.4Enzymenames
B symbolfor 1 Napierian absorbance (see absorbance). Alternative names may be listed following the headword,
2magneticflux density(bolditalic). whichisnormallytherecommendedname;otherwisealterna
• Where the same basic term is used in different typefaces, tivenamesincludetherecommendedname(iftheheadwordis
suchasroman/italic, oruppercase/lowercase, oras apre the common name), the systematic name, and other names.
fix or suffix, each usage is given as a separate headword. TheECnumberisalsogiven.
Forexample,h, h,H,andHeachhaveaseparateentry.
2.4 Multiple definitions
• Theorderinwhichsuchentriesaregivenislistedinsection
1.5. • Where a term has more than one meaning, the different
sensesarenumberedwithboldArabicnumerals.
2.3 Alternative terms and variant spellings blockade 1 (in pharmacology) the saturation of a spe
cific type of receptor with an antagonist to its normal
2.3.1 Choiceofheadword agonist. 2 (in immunology) the overloading or satura
tion of the reticuloendothelial system with inert par
Wherealternative terms for a headword, or variantspellings
ticles, such as carbon particles. 3 to impose any such
ofit,exist(seesection1.3),theheadwordselectedforthemain blockade.
entryisgenerally the recommended or preferred term, orthe • Theorderofthenumberedentriesisgenerallydetermined
onejudged to bethe commonest. Exceptions to this general bytheirbiochemicalsignificance.
izationarethose instanceswhere thenameofaGreekalpha
• Thedifferentsensesmaybefurthersubdividedintodef. la,
beticcharacteriswrittenoutforconvenienceofindexing:
def. 1b,etc.
beta globulinor ~globulin.... di+ comb.form 1(in chemicalnomenclature) (distinguish
from bis+ (def. 2)) a indicating the presence in a mol
2.3.2General
eculeoftwo identicalunsubstitutedgroups, e.g. diethyl
Any alternative terms and alternative spellings are listed sulfide, 1,3-dihydroxyacetone.bindicatingthepresence
followingtheheadwordinbold,seriftype: in a molecule of two identical inorganic oxoacid
residues in anhydride linkage, e.g. adenosine 5'-diphos
retrovirus or ribodeoxyvirus or RNA-DNA virus any
virusbelongingtothefamily Retroviridae.... phate. 2 or bis+ (def. I) denoting two, twofold, twice,
doubled.
Notes regarding the usage of these alternatives may be
• Homographsarenotdistinguished.
giveninbracketsand initalics;forexample
DNAglycosylase or (sometimes) DNAglycosidaseany 2.5 Hidden entries
ofagroupofenzymes....
bacteremia or (esp. Brit.) bacteraemia the presence of Hiddenentriesareterms that are notdefined attheirnormal
live bacteriain the blood. headwordposition. Instead,theyaretreated(implicitlyorex-
ix
GuidetotheDictionary
plicitly) at some other headword. They are set in bold serif usedassymbols. Ingeneral, the term 'symbol'isusedhere
type. Inthefollowingexample, 'bentoniteflocculationtest' is for
thehiddenentry:
unitsandtheirdecimalprefixes(e.g. m,mol; ~, M)
bentonite a colloidal, native hydrated aluminium sili
cate clay consisting principal1y of montmorillonite, a physicalquantitiesandconstants(e.g.a,H;k, R)
complex aluminosilicate, Alz03-4SiOz'H20, which has mathematicalfunctions (e.g. exp,In)
markedadsorptive properties. Itis used as an inhibitor
ofnucleasesand also inthebentoniteflocculation test, a chemicalelements(e.g. K, Mg)
passive agglutination test in which antigen-coated ben
groupsoflettersthatcanbeusedinplaceofachemical
toniteparticlesareused to detectspecificantibody.
group or compound in an equation or formula (e.g.
CoA,Me)
2.6 Other information
recommended abbreviations for nucleotides, bases, or
2.6.1 Plurals aminoacids.
The plural form (or forms) ofa headword is (are) given in • The symbols for SIbase and derived units and their deci
parenthesis following the headword ifits formation is non mal prefixes are mandatory; all other symbols are recom
standard, e.g. for Latin headwords, or where there is more mendations of IUBMB or IUPAC. In conformity with
thanoneformoftheplural. these recommendations, symbols for physical quantities
medulla(pl. medullasor medullae) the innermost partof and fundamental physical constants are printedin a slop
an organ, tissue, or structure; marrow, pith. ing(italic)typeface.
medullaryad).
• No distinction is made between acronyms, contractions,
2.6.2Affixesandcombiningforms abbreviations,etc.Allareclassedasabbreviations. Abbre
viations formed from the initial letters of two or more
• In common with other dictionaries, this Dictionary lists
words are printedwithoutperiods (full-stops), inlinewith
anddefinesmanywordelementsthatareused tocompose
contemporary practice, but abbreviations that are short
termsortomodifyexistingterms.Theseareeithercombin
enedforms ofsinglewordshaveaterminalperiod.
ingforms (whicharederivedfromparentwords)oraffixes
(infixes, prefixes, and suffixes, none of which have par • Inadditiontorecommendedabbreviations,theDictionary
ents). listsaselectionofotherscommonlyencounteredinthesci
• Theusuallexicographicalconventionistoaddahyphento entificliterature.
suffixes and combining forms when listing them as head
words, although generally the hyphen is omitted in for 2.6.4Derivedterms
mation ofcomposite terms. However, chemical and bio Derivedtermsnotmeritingseparatedefinitionarelistedatthe
chemicalterminologyalsoincludesaconsiderablenumber end ofthe entry for the parent term, preceded by a bold em
ofspecialized affixes that retain the hyphen in the forma dash and followed by an abbreviation indicating the part of
tionofcompositeterms(e.g.'meso-'in'meso-cystine'). speech.
In order to make an explicit distinction between these al
bactericideor bacteriocideany agent (biological, chem
ternatives, this Dictionarydepartsfrom thecommon con ical, or physical) that destroys bacteria. -bactericidal
ventionbyaddingahyphentoanaffixinaheadwordonly orbacteriocidalad).
whenalinkinghyphenisretainedinacombination:
2.6.5Etymology
meso-abbr.: ms-; prefix (in chemicalnomenclature) des
ignating a substance whose individual molecules con • Generally, the derivation ofwords is notexplained in en
tain.... tries. The exceptions are for eponymous terms and other
Bycontrast,combiningforms (e.g., 'meso'in 'mesoderm') entriesofparticularetymologicalinterest.
together with affixes producing unhyphenated composite
• Theetymologyisgivenwithinsquarebracketsattheendof
terms, are listed with an added plus sign, placed after
theentry.
and/orbeforetheword-elementasappropriate:
lIngstrom orAngstromsymbol: A; aunit oflen~thequal
meso+ or (sometimes before a vowel) mes+ comb. form to 10 10 metres. '" [After Anders Jonas Angstrom
denotingmiddle, orintermediate. (1814-74), Swedish physicist noted for his work on
+agogue or (US) +agog suffix denoting an agent that spectroscopy.]
elicitsorenhancesthesecretionof....
• Greekelementsofetymologiesaretransliterated:
2.6.3Abbreviationsandsymbols chirality topological handedness; the property of non
identity of an object with its mirror image.... [From
• Whereatermmaybeabbreviatedorindicatedwithasym Greek kheir, hand.]
bol, thisisnotedaftertheheadword.
nuclear magnetic resonanceabbr.: NMR ornmr; the 2.6.6Usage
phenomenonthat occurswhen atomicnuclei.... • Thefieldwithinwhichthetermisusedmaybespecifiedin
electric potentialorpotentialsymbol: Vor f; thework italicsandinparenthesisbeforethedefinition.
done in bringing unitelectriccharge.... malonyl 1 (in hiochemistry) the univalent acyl group,
• Thedistinctionbetweenan abbreviationandasymbolisa HOOC-CHz-CO-,derivedfrom malonicacidbylossof
littleblurred,sincesomeabbreviations(e.g.Ig)alsomaybe one hydroxyl group. 2 (in chemistry) the bivalent acyl