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1、GeneralPropertiesofCaseinGeneralPropertiesofCaseinThefourmaintypesofcaseincompriseapproximately80%ofthetotalproteininbovinemilk.Theremainingproteincomponentsaretermedwheyproteins;α-Lactalbumin:~2%β-lactoglobulin:~10%Serumalbumin:~1%Immunoglobulins:~2%OtherProteins:~2%Inmilk,caseinsexistasthecalcium
2、saltarrangedinmicellarparticlessurroundedbysolublekappa-casein.Thecaseincomponentofmilkisrelativelyheat-stable,capableofsurvivingpasturizationat~62-71 °C.Converselythewheyproteincomponentisdenaturedatthesetemperatures.Ingeneral,caseinshavelimitedα-helixandβ-sheetsecondarystructure.Theytendtobehighi
3、nprolinecontentandhaveveryfewdisulfidebonds.CaseinsolubilityispHdependentandisalsoaffectedbyionicstrengthandcomposition. AdditionofsodiumchloridewillaffectsolubilitydifferentlydependingonwhenitisaddedtothesolutionduringpHadjustment.J.DairySci., 77,1218,1994.CaseinTypesFourdifferenttypesofbovinecase
4、inexist,eachwithseveralgeneticvariants.TypeMol.wt.pIPhosphates/moleE1%gprotein/Linskimmilkα-s122,068-23,7244.2-4.768-1010.0-10.112-15α-s225,230 10-13 3-4β23,944-24,0924.6-5.14-54.5-4.79-11κ19,007-19,0394.1-5.8110.52-4J.DairySci., 67,1599-1631,1984,andfromTable1, J.DairySci., 68,2195-2205,1985.(NOTE
5、:geneticvariationsandvariablephosphorylationaccountforsomeoftherangesgiven.)α-s1Casein α-s1Caseinisthemostprevalentformofcaseininbovinemilk.Ithasbeenreportedtoexhibitantioxidantandradicalscavengingproperties.1 Ithasalsobeenreportedtobeinvolvedinthetransportofandcaseinfromtheendoplasmicreticulumtoth
6、eGolgiapparatus.2α-s2Casein Proteolyticfragmentsofα-s2Caseinhavebeenshowntoexhibitantibacterialactivity.Specificallythe39aminoacidcasocidin-1peptidefragmenthasbeenshowntoinhibit E.coli and Staph.carnosis growth.3β-Casein β-Caseinanditsfragmentshavebeenimplicatedinanumberofbiologicalfunctions.Thecas
7、oparanpeptidehasbeenreportedtoactivatemacrophagephagocytosisandperoxiderelease.Casohypotensinandcasoparanmaybeinvolvedin bradykinin regulation.Casohypotensinhasalsobeenshowntobeastronginhibitorofendo-oligop
