Incorporation of C14-l-leucine into protein by cell-free systems from sea urchin embryos at different stages of development☆

[摘要] Inthepresenceofadenosinetriphosphateandphosphoenolpyruvate,C14-l-leucinewasincorporatedintoproteinbyhomogenatesofPsammechinuseggsandembryos.Theincorporationwasinhibitedbyribonuclease.Particularlyinunfertilizedeggs,aconsiderablepartoftheincorporationactivitywaslocalizedincomponentsofhomogenatessedimentingat12000g.Inhomogenatespreparedinstronghypotonicity,lessoftheincorporationactivitywassedimentable.Whenhomogenateswerepreparedinparallelfromunfertilizedandfertilizedeggs,thehomogenatesoffertilizedeggsshowedasignificantlyhigherincorporationactivity.Theleucine-incorporatingactivityofthehomogenates,asmeasuredundertheseexperimentalconditions,rapidlyincreasedduringtheearlystagesofdevelopment.Theincreasebegansoonafterfertilizationandculminatedinthelateblastulastage.Theincreasewasnotessentiallyduetomoreefficientaminoacidactivation;itwasequallyobviousinincorporationsystemsfortifiedwithlivercellsapasasourceofactivatingenzymes.Theincreaseisprobablyattributabletoahighercontentofactiveribonucleoproteinparticlesintheembryos,sinceitwasalsoobservedinincorporationexperimentswithlivercellsapcombinedwithpartiallypurifiedribonucleoproteinparticlesfromtheembryos.

[学科分类] 生物科学（综合）

[关键词] ATP;adenosine triphosphate;PEP;phosphoenol pyruvate;RNA;ribonucleic acid;RNAse;ribonuclease;RNP-particles;ribonucleoprotein particles;TCA;Trichloroacetic acid;tris;tris(hydroxymethyl)-aminomethane