Differentiation of creatine phosphokinase during myogenesis: Quantitative fractionation of isozymes☆
[摘要] Atechniqueisdescribedforthequantitativemeasurementofcreatinephosphokinase(CPK)isozymesinextractsofchickmuscle.TheisozymesarefractionatedbystepwiseelutionwithincreasingsaltconcentrationsfromDEAE-Sephadexminicolumns.Isozymeseparationwasconfirmedbypolyacrylamidegelelectrophoresisfollowedbyenzymestaining.WeusedthismethodtodeterminechangesinCPKisozymesduringthecourseofmyogenesisinculture.ThetotalspecificactivityofCPKincreasesabout20-foldduringmyogenesis.Quantativeanalysisofisozymechangesshowsthatthemuscle-specificform(MM)accountsforvirtuallyallofthisincrease.ActivityofMM-CPKisundetectablein1-daycultures,increasesrapidlyaftermyoblastfusion,andcomprisesmorethan70%oftotalCPKinmaturecultures.Incontrast,thespecificactivityofthebrain-specificisozyme(BB)remainsconstantthroughoutmyogenesis.ThiswasinterpretedasindicatingthattheBsubunitisexpressedinbothmononucleatedcellsandmyotubes.WeconfirmedthisbyanalyzingCPKisozymesinfibroblastculturesandinmyotube-enrichedcultures.EliminationofmostofthemononucleatedcellsintheculturesproducedanincreaseinthespecificactivityofCPK,buthadnoeffectontheisozymepatternanddidnotdecreasetherelativeamountoftheBBisozyme.PurefibroblastculturescontainedverylowCPKactivity,predominantlytheBBisozyme.
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[效力级别] [学科分类] 生物科学（综合）
[关键词] [时效性]
