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24520059JournalofFoodScienceandBiotechnologyVol.24No.5Sep.2005:167321689(2005)0520102205:2004212201;:2005201220.:(19632),,,,;3.,3(,214036):,.pH,,,,.:2;;;:TS20213:AResearchonColorFixationofHistidineasaSubstituteforNitriteYANGXi2hong,XIAWen2shui(SchoolofFoodScienceandEngineering,SouthernYangtzeUniversity,Wuxi214036,China)Abstract:Nitritewassubstitutedbyhistidinetoformligandcomplexwithhemoglobinforcolorfixation1pHinfluenceonabsorptionspectrawasstudiedandtheequilibriumconstantswascalculated.Bydetectingabsorptionatdifferencetemperature,thestandardmolecularenthalpychangeandstandardentropychangewerecalculated,andtheresultsindicatedthatthereactionwasarHmandrSmreducingcourse.Keywords:hemoglobin2histidineligandcomplex;equilibriumconstants;enthalpy;entropy,,(),().,,[1].,[2].,.4,,,.,,,,,[3].,[3].,.,,,.6,,[4,5].,O2CONO,-OH-SH-NH-CN,[6].,,.,.[7].,.,,[8],,,.,[9],,,.,.11.1:;:.,,732,0105mol/LNH4OH,2%;:Sigma;.1.21.2.1015%,3000r/min10min,.,,,.3,30min,,.,,6030min,,3000r/min15min,,.1.2.2pH510-4mol/L,2mLpH5.09.00.02mol/LNa2HPO42KH2PO47mL,1mmol/L1mL,500600nm.1.2.3[10,11],,n=1,:HbHisWHb-His(1)lg((Ac-Ao)/(A-Ac))=nlgcHis+lg(2)A.AcA,lg((Ac-Ao)/(A-Ac))lgcHis,.,510-5mol/L,110-4110-3mo1/L;25011.11214(1)[12,13],:Gm=-RTlnK=Hm-TSm(3)lnK1/T,rHmrSm.1.2.5101,pH615,30min,015%1%,4.[14].1.31.3.1280nm.1.3.2540nm.1.3.3[15].22.1,,.A540A280,A540/A280,1.A540/A280,,.,,.,3015,.1,60,A540/A280,.1A280A540Tab.1Absorptionat280540nmandtheratioofsamplesunderdifferenttreatmethodsA540A280A540/A280012271106001214015131150401341015361153101350016101157701386600156511410014010156811405014042.2pH2pH,,2[16].pH21.540nm,pH,2.1pH2Fig.1AbsorptionofHb2HisligandcomplexatdifferentpH12,pH5,N,,,,.pH,pH615,540nm,2pH2540nmFig.2InfluencesofpHonA540ofHb2Hisligandcom2plex,[16],N-HpKa614,pH615,,pH,N-H,,,.213pH615,,(1)3.3Fig.3Absorptionofthecomplexunderdifferentcon2centrationofHis,Soret,Q,NOCN2[5].465,525,585nm,,,,-.lg((Ac-Ao)/(A2Ac))lgcHis,4.:y=019353x+315641=3166103.,pKa.,(pKa),,.40124,,.,,,,Fe(),2Fe()dz3,[17].,.019353,1.n1,.42lg((Ac-Ao)/(A-Ac))lgcHisFig.4Relationoflg((Ac-Ao)/(A-Ac))andlgcHisforcoordinationreactionofHbandHis21415,20,25,30,ln1/T,5.5ln1/TFig.5Relationoflnand1/TforcoordinationreactionofHbandHisy=11688x-301988,rH0mrS0m,2.52,,,.,,[5].[16],C4v,-D4h,,,rH0m0.,,,,rS0m0.2Tab.2TheequilibriumconstantsstandardmolecularenthalpyandentropychangeatdifferenttemperatureLn/((mol-2L2)10-3)15202530-rH0m/(kJ/mol)-rS0m/(J/molK)r0193531412711231661193971001257019992215,2[14],.,2136g/kg15%8115%.,,,,,.31)60,.2)pH2,pH=615,.3)3166103,,,.n1,,.4)rH0m=-9710,rS0m=-01257,0,.5015:[1]ShahidiF,PeggRB1Novelsynthesisofcookedcured2meatpigment[J].JournalofFoodScience,1991,56(3):1205-1212.[2].[J].,1994,21(2):199-205.[3],,,.(HbNO)NO22[J].,2001,22(7):67-70.[4]FuhrhopJH,SmithKM.PorphyrinsandMetalloporphyrins[M].NewYork:ElsevierScientificPublishingCo.,1975.[5],.[J].,2003,23(5):377-378.[6],,.CO,NO[J].,1990,48(10):459-465.[7].[J].,1998,24(6):655-658.[8],.[J].(),2002,22(5):103-105.[9].[J].,2000,16(4):74-76.[10],,.()[J].,1995,11(3):67-69.[11],,.N[J].,1995,11(2):192-197.[12],.[J].,1996,10(4):1608-1612.[13],,,.()[J].,1993,14(8):1055-1057.[14],,.[J].,1999,16(3):109-111.[15].[M].:,1998.[16],.[M].:,2002.[17].[M].:,1992.[18].[M].:,2000.(:)(101)[3]KrinskyNI.Overviewoflycopene,carotenoids,anddiseaseprevention[J].ProcSocExpBiolMed,1998,218:95-97.[4]MohitpalSingh,RKrishanappa.Efficacyoforallycopeneinthetreatmentoforalleukoplakia[J].OralOncology,2004,40:591-596.[5]HumbertoRMatos.LycopeneinhibitsDNAdamageandlivernecrosisinratstreatedwithferricnitrilotriacetate[J].Ar2chivesofBiochemistryandBiophysics,2001,396:171-177.[6]VanDenBerg.Thepotentialfortheimprovementofcarotenoidlevelsinfoodsandthelikelysystermiceffects[J].JSciFoodAgric,2000,80:880-912.[7]AlbrechtM.MetabolicengineeringoftheterpenoidbiosyntheticpathwayofEscherichiacoliforproductionofthecarote2noidsb2caroteneandzeaxanthin[J].BiotechnolLett,1999,21:791-795.[8],[M].:,1998.[9],,.22[J].,2002,23(5):302-306.[10]AndreaMele,RanieroMendichi,AntonioSelva.Non2covalentassociationofcyclomaltooliogosaccharides(cyclodextrins)withtrans22caroteneinwater:evidencefortheformationoflargeaggregatesbylightscatteringandNMRspectroscopy[J].CarbohydrateRes,1998,310:261-267.[11]AndreaMele,RanieroMendichi,AntonioSelva,etal.Non2covalentassociationofcyclomaltooliogosaccharides(cyclo2dextrins)withcarotenoidsinwater.Astudyonthe2and2cyclodextrin/,2carotene(lycopen)systembylightscat2teringionsprayionizationandtandemmassspectrometry[J].CarbohydrateRes,2002,337:1129-1136.[12].[D]::,2000.[13]RosenbergM.Microencapsulatingpropertiesofwheyprotein:Microencapsulatingofanhydrousmilkfat[J].JofDairySci,1993,76(10):2868-2885.[14]BohmV.IntestinalAbsorptionofLycopenefromDifferentTypesofOleoresinCapsules[J].JFoodSci,2002,67:1910-1913.(:)60124