Compartmentation of thymidine kinase in unfertilized sea urchin eggs and possible release of thymidine kinase from particulates in activated eggs

[摘要] Thethymidinekinaseactivityofhomogenatesofunfertilizedeggsoftheseaurchin,Hemicentrotuspulcherrimus,in1MNaClwasalwayslowerthanthatofhomogenatesoftheunfertilizedeggsinhypotonicmediaorhomogenatesofthefertilizedorammonia-activatedeggsin1MNaClby30–50%.Sonicationoftheunfertilizedegghomogenatesin1MNaClresultedintheelevationofthymidinekinaseactivityuptoalevelinthefertilizedorammonia-activatedegghomogenateswhichisnotaffectedbysonication.Differentialcentrifugationofunfertilizedegghomogenatesin1MNaClrevealedthatthelatentthymidinekinaseisassociatedwiththe1500gpelletorevenwiththe200gpellet.Exposureofthe1500gpellettosonication,hypotonicmedia,0.3%TritonX-100in1MNaCl,and2Mpropyleneglycolresultedintheelevationofthymidinekinase,whichwaseventuallyshowntobenolongerboundtothepelletfraction.Latentthymidinekinasewasnotdetectedinthe1500gpelletpreparedfromthefertilizedegghomogenatein1MNaCl.Thesefindingsseemtosuggestthatthymidinekinaseinunfertilizedeggsmaybesequestered,atleastpartly,insomelargeintracellularstructuresbutmaybereleasedfromthemuponfertilizationorammoniaactivation,inaccordancewithourearlierobservationontheapparentactivationofthymidinekinaseaferfertilization.

[学科分类] 生物科学（综合）