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1、ErwiniarhaponticiE602株β-半乳糖苷酶的分离纯化及性质研究//.paper.edu-1-中国科技论文在线PurificationandCharacterizationofanovelβ-galactosidasefromthenewlyisolatedstrainErwiniarhaponticiE602#**JIANGYike,XIAYu(SchoolofFoodScienceandTechnology,JiangnanUniversity,JiangsuWuxi214122)5Foundations
2、:NationalNaturalScienceFoundationofChina(No.31000752);NationalResearchFoundationfortheDoctoralProgramofHigherEducationofChina(No.200802951022);ScienceandNatureFoundationinJiangsuProvince(No.BK2008103).Briefauthorintroduction:JiangYike(1989-),Male,Undergraduatestud
3、entinSchoolofFoodScienceandTechnology,JiangnanUniversityCorrespondanceauthor:XIAYu(1975-),Male,AssociateProfessor,SchoolofFoodScienceandTechnology,JiangnanUniversity.E-mail:yuxia@jiangnan.eduAbstract:Aβ-galactosidaseproducingbacterialstrainE602wasisolatedfromfroze
4、nsoilandidentifiedtobeErwiniarhapontici.Thisstrainwasculturedat26℃withtheinductionoflactoseforproductionoftheβ-galactosidase.Thisenzymewasthenpurifiedwithammoniumsulfatefractionation,ionexchangeandgelfiltrationchromatographyforfurtherstudiesoftheenzymaticcharacter
5、istics.Thepurifiedenzymehadamolecularweightofabout100kDa.TheoptimumreactiontemperatureandpH10ofthisenzymewas40℃andpH7.0respectively,indicatingthatthisenzymewasamesophilicneutralβ-galactosidase.However,theenzymeretainedabout15%activityat10℃,whichalsosuggestedcold-a
6、daptivepropertyofthisenzyme.KineticsofthisenzymewasstudiedandtheKmandVmaxofthisenzymewas0.21mmol/Land263.16??mol/mgmin-1.MetalionssuchasLi+,K+,Mg2+andZn2+canactivatetheenzymaticactivityobviously,whileCu2+andFe2+inhibitedtheactivity.Thelactose15hydrolysisinmilkhadb
7、eenalsoinvestigatedandresultssuggestedthatthisenzymemaybesuitableformilkprocessing.Keywords:β-Galactosidase;Erwiniarhapontici;IsolationandPurification;EnzymaticCharacteristics0Introductionβ-galactosidase(EC3.2.1.23)isakindofglycosidehydrolasewhichcanhydrolyze20β-1
8、,4-D-galactosidiclinkageinlactose[1].Thisenzymeisappliedindairyindustryforeliminationofmilklactoseinordertopreventthesymptomoflactose-intoleranceinhuman
