A mitochondrial factor that prevents the effects of antimycin A on myogenesis

[摘要] AntimycinA,togetherwithanumberofotheragentswhichinterferewithorinhibitoxidativephosphorylationinisolatedmitochondrialsystems,alsointerfereswithnormaldevelopmentofmyogenicelementsinexplantedchickembryosandmonolayerculturesofmuscle.Theeffectsoftheseagentsarequantitative,bothmorphologicalandbiochemicalindicesbeingused,atmillimolartomicromolarconcentrations.Itisconcludedthatnormalgrowthandmaintenanceofmyogenicelementsinitiallyrequirestructuralintegrityaswellasabalancedoxidativestateofmembraneelementsinvolvedinaerobicphosphorylation.AfactorisolatedfromaqueousextractsofchickenlivermitochondriaaffordsprotectionagainstantimycinA.Embryoscultivatedinamediumcontainingasmuchas0.035μgoftheinhibitorpermilliliterfor6hours,andtransferredtonormalmediumcontainingthefactor,recover.ThefactoralsopreventstheactionofantimycinAinmonolayerculturesofembryonicskeletalmuscle.Itdoesnotprotectembryosagainsteffectsofoligomycin.ThefactorisisolatedandpurifiedbypassagethroughaSephadexG-200column,followedbyadsorptiononhydroxyapatitecolumnsandstepwiseelutionwithphosphatebuffer.Theproteincomingoffataconcentrationof0.06Mphosphate,pH7.3,isactiveandcanbetreatedwithlightpetroleumetherfollowedbydialysisagainst0.002Mphosphatewithoutlossofactivity.Activityislostin30minutesatpH4(25°C),butatpH5.5noreductioninactivityisobserved.Activityisdestroyedbyheatingat60°Cfor15minutes.NeitherDNaseandRNaseaffecttheactivityofthefactor;itisnotdestroyedcompletelybymildtrypsintreatment.Thefactorisantigenic,and,bymeansofantibodiesmadetoitinrabbits,ithasbeenshownthatthefactoroccursnormallyintheearlychickembryo.

[学科分类] 生物科学（综合）