Limited proteolysis of some egg surface components is an early event following fertilization of the sea urchin, Strongylocentrotus purpuratus☆

[摘要] ThesurfaceproteinsofeggsfromStronglocentrotuspurpuratuswerelabeledwith125Ibylactoperoxidase-catalyzediodination.Theeggswereexaminedaftersolubilizationanddisaggregationinsodiumdodecylsulphate(SDS)byelectrophoresisonSDS-polyacrylamideslab-gels.Seventy-fivepercentofthelabelwasfoundinmaterialwithamolecularweightgreaterthan130,000.About5%oftheradioactivitywasexcludedfromthegels.Uponfertilization,embryosshowaredistributionoftheradioactivelylabeledspecies.Thereisadecreaseintheamountofveryhighmolecularweightmaterialbutanincrease(35–40%)inmaterialexcludedfromthegel.Inaddition,newradioactivebandsoflowermolecularweightarefound.Thischangeofdistributionintheradioactivebandsisblockedbyinclusionofsoybeantrypsininhibitoreitherbeforeorimmediatelyafterfertilization,whichcompletelyinhibitsthecorticalgranuleprotease.Thedisappearanceofhighmolecularweightcomponentsispreventedbytreatmentoftheeggswithprocaineduringfertilization,althoughtheappearanceoflowmolecularweightbands(approximately20,000and30,000)isnotcompletelyblockedbyprocainetreatment.Parthenogenicactivationofeggsbybutyricacidorpartialmetabolicactivationbyammoniaeachleadstochangesintheeggsurfaceproteinswhicharesimilarbutnotidenticaltothoseseenafterfertilization.Thedatasuggestthatthelabelingoccursonthevitellinemembrane,plasmamembraneandjellylayer.Thepossiblesignificanceoflimitedproteolysisinfertilizationisdiscussed.

[学科分类] 生物科学（综合）