酪蛋白ACE抑制肽的類蛋白反應修飾與溶劑分級研究.pdf

1、東北農(nóng)業(yè)大學碩士學位論文酪蛋白ACE抑制肽的類蛋白反應修飾與溶劑分級研究姓名：孫輝申請學位級別：碩士專業(yè)：食品科學與工程；食品科學指導教師：趙新淮20120610ABSTRACT詈寡詈!!詈!皇!!皇!!皇苧!皇!!鼉詈!!曼!烹詈!皇!!鼉!!皇曼!鼉!鼉詈!!暑苧鼉曼!曼曼!!曼苧!暑!竺詈曼!!!苧詈詈!詈詈!!曼!!詈!!苧!!!詈曼!詈!詈!詈!!!苧AStudyonthePlastein—ReactionandSolvent

2、FractionationoftheACE—Inhibitory7PeptidesDerivedfromCaseinAbstractInthepastmanystudieshavebeencarriedouttoshowthatcaseinwasagoodsourceofACEinhibitorypeptidesInordertoenhanceACEinhibitoryactivityofapreparedcaseinhydrolysa

3、te，plasteinreactionwasappliedonthecaseinhydrolysateinthepresenceofprolineinthepresentworkSolventfractionationwasemployedtotreatthe：modifiedcaseinhydrolysateEnzymaticresistanceoftheobtainedproductswasanalyzedtoinvestigate

4、theimpactsoftheconductedtreatmentonACE—inhibitoryactivityofthemodifiedorfractionatedproductsAcaseinhydrolysatewaspreparedbyhydrolyzingcaseinwithAlcalaseandthenmodifiedbyallAlcalase—catalyzedplasteinreactionThepreparedcas

5、einhydrolysateofareactiontimeof6hhadadegreeofhydrolysisof109％andIC50valueof526tg／mL。Withthedecreasedamountoffreeaminogroupsofthemodifiedhydrolysateastheresponseandthereactiontimefixedat6h，andresponsesurfacemethodologyWaS

6、usedtooptimizethereactionconditionsTheoptimizedconditionswereallenzymeadditionof31kU／gproteins，reactiontemperatureof25oC，andcaseinhydrolysatesconcentrationof50％(w／v)respectivelyThemaxinmmdecreasedamountoffreeaminogroupso

7、fthemodifiedhydrolysatepreparedundertheseoptimizedconditionswas1121pmol／gproteinsCaseinhydrolysateWaSmodifiedatdifferentextentsbytheplasteinreactioninprolineadditionleveof06tool／toolfreeaminogroupsTheACEinhibitoryactivit

8、iesandIC50valuesofthemodifiedhydrolysateswereassayedTheACE—inhibitoryactivitiesofallthemodifiedhydrolysatesincreaSedaSthereactionextentincreasedandwerehighel。thantheoriginalhydrolysatesAmodifiedhydrolysatewithoutprolineh

9、adfreeaminogroupsabout16688gmol／gproteinsandadecreaSedIC50valueof149，tg／mLAmodifiedhydrolysateinthepresenceofprolinehadfreeaminogroupsof15933pmol／gproteinsandadecreasedIC50valueof130gg／mLTheoriginalhydrolysateandthemodif

10、iedhydrolysatesofthehighestactivitywerefractionatedintosupernatantandprecipitationbyethanolormethanol—watersolventsinvolumeratiosof3：7，5：5and7：3respectivelyThemodifiedhydrolysatewasalsofractionatedbypurewaterandservedasa

11、contr01Thepeptiderecoverycontentoffreeaminogroups，ACE—inhibitoryactivityandICsovalueofthefractionatedhydrolysateswereanalyzedFractionationoftheoriginalhydrolysatebythetwosolventsf7：3ethan01ormethan01waterv／v)ledtothesolu