Bioinorganic Chemistry - Inorganic Elements in the Chemistry of Life: An Introduction and Guide

425 Pages·2013·42.963 MB·English

by  Wolfgang Kaim, Brigitte Schwederski, Axel Klein

Wolfgang KaiM
bRigitte sCHWedeRsKi
axel Klein
seCond edition
BIOINORGANIC CHEMISTRY:
INORGANIC ELEMENTS
IN THE CHEMISTRY OF LIFE
an intRoduCtion and guide
inoRganiC CHeMistRy
a Wiley textbooK seRies

Bioinorganic Chemistry: Inorganic Elements in
the Chemistry of Life
Inorganic Chemistry
AWileySeriesofAdvancedTextbooks
ISSN:1939-5175
EditorialBoard
DavidAtwood,UniversityofKentucky,USA
BobCrabtree,YaleUniversity,USA
GerdMeyer,UniversityofCologne,Germany
DerekWoollins,UniversityofSt.Andrews,UK
PreviouslyPublishedBooksinthisSeries
StructuralMethodsinMolecularInorganicChemistry
DavidW.H.Rankin,NorbertW.Mitzel&CaroleA.Morrison;ISBN:978-0-470-97278-6
IntroductiontoCoordinationChemistry
GeoffreyAlanLawrance;ISBN:978-0-470-51931-8
ChiralityinTransitionMetalChemistry
HaniAmouri&MichelGruselle;ISBN:978-0-470-06054-4
BioinorganicVanadiumChemistry
DieterRehder;ISBN:978-0-470-06516-7
InorganicStructuralChemistry2ndEdition
UlrichMu¨ller;ISBN:978-0-470-01865-1
LanthanideandActinideChemistry
SimonCotton;ISBN:978-0-470-01006-8
MassSpectrometryofInorganicandOrganometallicCompounds:Tools-Techniques-Tips
WilliamHenderson&J.ScottMcIndoe;ISBN:978-0-470-85016-9
MainGroupChemistry,SecondEdition
A.G.Massey;ISBN:978-0-471-19039-5
SynthesisofOrganometallicCompounds:APracticalGuide
SanshiroKomiya;ISBN:978-0-471-97195-5
ChemicalBonds:ADialog
JeremyBurdett;ISBN:978-0-471-97130-6
TheMolecularChemistryoftheTransitionElements:AnIntroductoryCourse
FrancoisMathey&AlainSevin;ISBN:978-0-471-95687-7
StereochemistryofCoordinationCompounds
AlexandervonZelewsky;ISBN:978-0-471-95599-3
Formoreinformationonthisseriessee:www.wiley.com/go/inorganic
Bioinorganic Chemistry:
Inorganic Elements in the
Chemistry of Life
An Introduction and Guide
Second Edition
Written and Translated by
Wolfgang Kaim
University of Stuttgart, Institute of Inorganic Chemistry,
Stuttgart, Germany
Brigitte Schwederski
University of Stuttgart, Institute of Inorganic Chemistry,
Stuttgart, Germany
Axel Klein
University of Cologne, Institute of Inorganic Chemistry,
Cologne, Germany
OriginallypublishedintheGermanlanguagebyVieweg+Teubner,65189Wiesbaden,Germany,as“WolfgangKaimandBrigitteSchwederski:
BioanorganischeChemie.4.Auflage(4thEdition)”.
©Vieweg+Teubner/SpringerFachmedienWiesbadenGmbH2005.
SpringerFachmedienispartofSpringerScience+BusinessMedia
Thiseditionfirstpublished2013
©2013JohnWiley&Sons,Ltd
FirstEnglishlanguageeditionpublished1994
Registeredoffice
JohnWiley&SonsLtd,TheAtrium,SouthernGate,Chichester,WestSussex,PO198SQ,UnitedKingdom
Fordetailsofourglobaleditorialoffices,forcustomerservicesandforinformationabouthowtoapplyforpermissiontoreusethecopyrightmaterialin
thisbookpleaseseeourwebsiteatwww.wiley.com.
TherightoftheauthortobeidentifiedastheauthorofthisworkhasbeenassertedinaccordancewiththeCopyright,DesignsandPatentsAct1988.
Allrightsreserved.Nopartofthispublicationmaybereproduced,storedinaretrievalsystem,ortransmitted,inanyformorbyanymeans,electronic,
mechanical,photocopying,recordingorotherwise,exceptaspermittedbytheUKCopyright,DesignsandPatentsAct1988,withoutthepriorpermission
ofthepublisher.
Wileyalsopublishesitsbooksinavarietyofelectronicformats.Somecontentthatappearsinprintmaynotbeavailableinelectronicbooks.
Designationsusedbycompaniestodistinguishtheirproductsareoftenclaimedastrademarks.Allbrandnamesandproductnamesusedinthisbookare
tradenames,servicemarks,trademarksorregisteredtrademarksoftheirrespectiveowners.Thepublisherisnotassociatedwithanyproductorvendor
mentionedinthisbook.
LimitofLiability/DisclaimerofWarranty:Whilethepublisherandauthorhaveusedtheirbesteffortsinpreparingthisbook,theymakenorepresentations
orwarrantieswithrespecttotheaccuracyorcompletenessofthecontentsofthisbookandspecificallydisclaimanyimpliedwarrantiesofmerchantability
orfitnessforaparticularpurpose.Itissoldontheunderstandingthatthepublisherisnotengagedinrenderingprofessionalservicesandneitherthe
publishernortheauthorshallbeliablefordamagesarisingherefrom.Ifprofessionaladviceorotherexpertassistanceisrequired,theservicesofa
competentprofessionalshouldbesought
Theadviceandstrategiescontainedhereinmaynotbesuitableforeverysituation.Inviewofongoingresearch,equipmentmodifications,changesin
governmentalregulations,andtheconstantflowofinformationrelatingtotheuseofexperimentalreagents,equipment,anddevices,thereaderisurgedto
reviewandevaluatetheinformationprovidedinthepackageinsertorinstructionsforeachchemical,pieceofequipment,reagent,ordevicefor,among
otherthings,anychangesintheinstructionsorindicationofusageandforaddedwarningsandprecautions.ThefactthatanorganizationorWebsiteis
referredtointhisworkasacitationand/orapotentialsourceoffurtherinformationdoesnotmeanthattheauthororthepublisherendorsestheinformation
theorganizationorWebsitemayprovideorrecommendationsitmaymake.Further,readersshouldbeawarethatInternetWebsiteslistedinthisworkmay
havechangedordisappearedbetweenwhenthisworkwaswrittenandwhenitisread.Nowarrantymaybecreatedorextendedbyanypromotional
statementsforthiswork.Neitherthepublishernortheauthorshallbeliableforanydamagesarisingherefrom.
LibraryofCongressCataloging-in-PublicationData
Kaim,Wolfgang,1951–
[BioanorganischeChemie.English]
Bioinorganicchemistry:inorganicelementsinthechemistryoflife:anintroductionandguide/
writtenandtranslatedbyWolfgangKaim,BrigitteSchwederski,AxelKlein.–Secondedition.
pagescm
Translationof:BioanorganischeChemie.
Includesbibliographicalreferencesandindex.
ISBN978-0-470-97524-4(cloth)–ISBN978-0-470-97523-7(paper) 1.Bioinorganicchemistry.
I.Schwederski,Brigitte,1959– II.Klein,Axel,1964– III.Title.
QP531.K35132013
572(cid:2).51–dc23 2013011894
AcataloguerecordforthisbookisavailablefromtheBritishLibrary.
HBISBN:9780470975244
PBISBN:9780470975237
Typesetin10/12ptTimesbyAptaraInc.,NewDelhi,India
1 2013
Contents
PrefacetotheSecondEdition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi
PrefacetotheFirstEdition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xiii
1 HistoricalBackground,CurrentRelevanceandPerspectives . . . . . . . . . . . . . . . 1
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2 SomeGeneralPrinciples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.1 OccurrenceandAvailabilityofInorganicElementsinOrganisms . . . . . . . . . . . 7
Insertion:TheChelateEffect . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Insertion:“Hard”and“Soft”CoordinationCenters . . . . . . . . . . . . . . . . . . 14
2.2 BiologicalFunctionsofInorganicElements . . . . . . . . . . . . . . . . . . . . . 14
2.3 BiologicalLigandsforMetalIons . . . . . . . . . . . . . . . . . . . . . . . . . . 16
2.3.1 CoordinationbyProteins-CommentsonEnzymaticCatalysis . . . . . . . . 17
Insertion:The“EntaticState”inEnzymaticCatalysis . . . . . . . . . . . . . . . . 20
2.3.2 TetrapyrroleLigandsandOtherMacrocycles . . . . . . . . . . . . . . . . 22
Insertion:ElectronSpinStatesinTransitionMetalIons. . . . . . . . . . . . . . . . 28
2.3.3 Nucleobases,NucleotidesandNucleicAcids(RNA,DNA)asLigands . . . . 31
Insertion:SecondaryBonding . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
2.4 RelevanceofModelCompounds . . . . . . . . . . . . . . . . . . . . . . . . . . 34
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
3 Cobalamins,IncludingVitaminandCoenzymeB . . . . . . . . . . . . . . . . . . . 37
12
3.1 HistoryandStructuralCharacterization . . . . . . . . . . . . . . . . . . . . . . . 37
Insertion:BioorganometallicsI . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
3.2 GeneralReactionsofAlkylcobalamins . . . . . . . . . . . . . . . . . . . . . . . 41
3.2.1 One-electronReductionandOxidation . . . . . . . . . . . . . . . . . . . 41
3.2.2 Co–CBondCleavage . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Insertion:ElectronParamagneticResonanceI . . . . . . . . . . . . . . . . . . . . 43
3.3 EnzymeFunctionsofCobalamins . . . . . . . . . . . . . . . . . . . . . . . . . . 45
3.3.1 Adenosylcobalamin(AdoCbl)-dependentIsomerases . . . . . . . . . . . . 45
Insertion:OrganicRedoxCoenzymes . . . . . . . . . . . . . . . . . . . . . . . . 48
3.3.2 AlkylationReactionsofMethylcobalamin(MeCbl)-dependentAlkyl
Transferases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
3.4 ModelSystemsandtheEnzymaticActivationoftheCo–CBond . . . . . . . . . . . 52
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
4 MetalsattheCenterofPhotosynthesis:MagnesiumandManganese . . . . . . . . . . . 57
4.1 VolumeandEfficiencyofPhotosynthesis . . . . . . . . . . . . . . . . . . . . . . 57
4.2 PrimaryProcessesinPhotosynthesis. . . . . . . . . . . . . . . . . . . . . . . . . 59
vi Contents
4.2.1 LightAbsorption(EnergyAcquisition) . . . . . . . . . . . . . . . . . . . 59
4.2.2 ExcitonTransport(DirectedEnergyTransfer) . . . . . . . . . . . . . . . . 59
4.2.3 ChargeSeparationandElectronTransport . . . . . . . . . . . . . . . . . . 62
Insertion:StructureDeterminationbyX-rayDiffraction . . . . . . . . . . . . . . . 65
4.3 Manganese-catalyzedOxidationofWatertoO . . . . . . . . . . . . . . . . . . . 67
2
Insertion:Spin–SpinCoupling . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
5 TheDioxygenMolecule,O :Uptake,TransportandStorageofanInorganic
2
NaturalProduct . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
5.1 MolecularandChemicalPropertiesofDioxygen,O . . . . . . . . . . . . . . . . . 77
2
5.2 OxygenTransportandStoragethroughHemoglobinandMyoglobin . . . . . . . . . 82
5.3 AlternativeOxygenTransportinSomeLowerAnimals:HemerythrinandHemocyanin 92
5.3.1 Magnetism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
5.3.2 LightAbsorption. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
5.3.3 VibrationalSpectroscopy . . . . . . . . . . . . . . . . . . . . . . . . . . 93
Insertion:ResonanceRamanSpectroscopy. . . . . . . . . . . . . . . . . . . . . . 93
5.3.4 Mo¨ssbauerSpectroscopy . . . . . . . . . . . . . . . . . . . . . . . . . . 94
Insertion:Mo¨ssbauerSpectroscopy . . . . . . . . . . . . . . . . . . . . . . . . . 94
5.3.5 Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
5.4 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
6 CatalysisthroughHemoproteins:ElectronTransfer,OxygenActivationandMetabolism
ofInorganicIntermediates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
6.1 Cytochromes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
6.2 CytochromeP-450:OxygenTransferfromO toNonactivatedSubstrates . . . . . . . 103
2
6.3 Peroxidases:DetoxificationandUtilizationofDoublyReducedDioxygen . . . . . . . 108
6.4 ControllingtheReactionMechanismoftheOxyhemeGroup:Generation
andFunctionofOrganicFreeRadicals . . . . . . . . . . . . . . . . . . . . . . . 110
6.5 HemoproteinsintheCatalyticTransformationofPartiallyReducedNitrogen
andSulfurCompounds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
Insertion:Gasotransmitters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
7 Iron–SulfurandOtherNon-hemeIronProteins . . . . . . . . . . . . . . . . . . . . . 117
7.1 BiologicalRelevanceoftheElementCombinationIron–Sulfur . . . . . . . . . . . . 117
Insertion:ExtremophilesandBioinorganicChemistry . . . . . . . . . . . . . . . . 118
7.2 Rubredoxins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
7.3 [2Fe-2S]Centers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
7.4 PolynuclearFe/SClusters:RelevanceoftheProteinEnvironmentandCatalyticActivity 123
7.5 ModelSystemsforFe/SProteins . . . . . . . . . . . . . . . . . . . . . . . . . . 128
7.6 Iron-containingEnzymeswithoutPorphyrinorSulfideLigands . . . . . . . . . . . . 130
7.6.1 Iron-containingRibonucleotideReductase . . . . . . . . . . . . . . . . . 130
7.6.2 SolubleMethaneMonooxygenase . . . . . . . . . . . . . . . . . . . . . 132
7.6.3 PurpleAcidPhosphatases(Fe/FeandFe/Zn) . . . . . . . . . . . . . . . . 133
7.6.4 MononuclearNon-hemeIronEnzymes . . . . . . . . . . . . . . . . . . . 133
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135
Contents vii
8 Uptake,TransportandStorageofanEssentialElement,asExemplifiedbyIron . . . . . 139
Insertion:Metallome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
8.1 TheProblemofIronMobilization:OxidationStates,SolubilityandMedicalRelevance 140
8.2 Siderophores:IronUptakebyMicroorganisms . . . . . . . . . . . . . . . . . . . . 141
Insertion:OpticalIsomerisminOctahedralComplexes . . . . . . . . . . . . . . . . 144
8.3 Phytosiderophores:IronUptakebyPlants . . . . . . . . . . . . . . . . . . . . . . 149
8.4 TransportandStorageofIron . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150
8.4.1 Transferrin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152
8.4.2 Ferritin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155
8.4.3 Hemosiderin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160
9 Nickel-containingEnzymes:TheRemarkableCareerofaLong-overlookedBiometal . . 163
9.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163
9.2 Urease . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164
9.3 Hydrogenases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166
9.4 CODehydrogenase=COOxidoreductase=Acetyl-CoASynthase . . . . . . . . . . 169
9.5 Methyl-coenzymeMReductase(IncludingtheF Cofactor) . . . . . . . . . . . . 172
430
Insertion:NaturalandArtificial(Industrial)C Chemistry . . . . . . . . . . . . . . 174
1
Insertion:BioorganometallicsII:TheOrganometallicChemistryofCobaltandNickel . 176
9.6 SuperoxideDismutase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177
9.7 ModelCompounds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178
FurtherReading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179
10 Copper-containingProteins:AnAlternativetoBiologicalIron . . . . . . . . . . . . . . 183
10.1 Type1:“Blue”CopperProteins . . . . . . . . . . . . . . . . . . . . . . . . . . . 186
Insertion:ElectronParamagneticResonanceII . . . . . . . . . . . . . . . . . . . . 187
10.2 Type2andType3CopperCentersinO -activatingProteins:OxygenTransport
2
andOxygenation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191
10.3 CopperProteinsasOxidases/Reductases . . . . . . . . . . . . . . . . . . . . . . . 195
10.4 CytochromecOxidase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200
10.5 Cu,Zn-andOtherSuperoxideDismutases:Substrate-specificAntioxidants . . . . . . 203
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207
11 BiologicalFunctionsofthe“Early”TransitionMetals:Molybdenum,Tungsten,
VanadiumandChromium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211
11.1 OxygenTransferthroughTungsten-andMolybdenum-containingEnzymes . . . . . . 211
11.1.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211
11.1.2 OxotransferaseEnzymesContainingtheMolybdopterinor
TungstopterinCofactor . . . . . . . . . . . . . . . . . . . . . . . . . . . 213
Insertion:“Oxidation” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214
11.2 MetalloenzymesintheBiologicalNitrogenCycle:Molybdenum-dependent
NitrogenFixation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219
11.3 AlternativeNitrogenases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226
11.4 BiologicalVanadiumOutsideofNitrogenases . . . . . . . . . . . . . . . . . . . . 229
11.5 Chromium(III)intheMetabolism? . . . . . . . . . . . . . . . . . . . . . . . . . 231
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232
viii Contents
12 Zinc:StructuralandGene-regulatoryFunctionsandtheEnzymaticCatalysisof
HydrolysisandCondensationReactions . . . . . . . . . . . . . . . . . . . . . . . . . 235
12.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235
12.2 Carboanhydrase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238
12.3 CarboxypeptidaseAandOtherHydrolases . . . . . . . . . . . . . . . . . . . . . 243
12.4 CatalysisofCondensationReactionsbyZinc-containingEnzymes . . . . . . . . . . 248
12.5 AlcoholDehydrogenaseandRelatedEnzymes . . . . . . . . . . . . . . . . . . . . 249
12.6 The“ZincFinger”andOtherGene-regulatoryZincProteins . . . . . . . . . . . . . 251
12.7 Insulin,hGH,MetallothioneinandDNARepairSystemsasZinc-containingProteins . 253
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 254
13 UnequallyDistributedElectrolytes:FunctionandTransportofAlkaliandAlkalineEarth
MetalCations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 257
13.1 CharacterizationandBiologicalRolesofK+,Na+,Ca2+ andMg2+ . . . . . . . . . . 257
Insertion:HeteroatomNuclearMagneticResonance . . . . . . . . . . . . . . . . . 262
13.2 ComplexesofAlkaliandAlkalineEarthMetalIonswithMacrocycles . . . . . . . . 264
13.3 IonChannels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267
13.4 IonPumps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 270
FurtherReading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273
14 CatalysisandRegulationofBioenergeticProcessesbytheAlkalineEarthMetalIons
Mg2+ andCa2+ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 277
14.1 Magnesium:CatalysisofPhosphateTransferbyDivalentIons . . . . . . . . . . . . 277
14.2 TheUbiquitousRegulatoryRoleofCa2+ . . . . . . . . . . . . . . . . . . . . . . 283
FurtherReading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291
15 Biomineralization:TheControlledAssemblyof“AdvancedMaterials”inBiology . . . . 295
15.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295
15.2 NucleationandCrystalGrowth . . . . . . . . . . . . . . . . . . . . . . . . . . . 299
Insertion:Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300
15.3 ExamplesofBiominerals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301
15.3.1 CalciumPhosphateintheBonesofVertebratesandtheGlobalPCycle . . . . 301
Insertion:TheGlobalPCycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305
15.3.2 CalciumCarbonateandtheGlobalInorganicCCycle . . . . . . . . . . . . 306
Insertion:TheGlobalCCycleandtheMarineInorganicCCycle . . . . . . . . . . . 307
15.3.3 AmorphousSilica . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 308
15.3.4 IronBiominerals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 309
15.3.5 StrontiumandBariumSulfates . . . . . . . . . . . . . . . . . . . . . . . 310
15.4 BiomimeticMaterials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 310
FurtherReading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 311
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 311
16 BiologicalFunctionsoftheNonmetallicInorganicElements . . . . . . . . . . . . . . . 315
16.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 315
16.2 Boron . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 315
16.3 Silicon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 315