Enzyme patterns in mitochondria of eggs, liver, and skeletal muscle during larvel development of Xenopus☆

[摘要] Thepurposeofthisinvestigationwastocomparethedistributionofselectedenzymesinmitochondriaofeggsandindifferentiatedlarvaltissues(liver,tailmuscle)ofXenopus.Tothisendthespecificactivitiesoffivematrixenzymes(glutamatedehydrogenase,glutamateoxaloacetatetransaminase,glutamatepyruvatetransaminase,3-hydroxyacyl-CoAdehydrogenase,andmalatedehydrogenase)andthreemembrane-boundenzymes(glycerolphosphatedehydrogenase,3-hydroxybutyratedehydrogenase,succinatedehydrogenase)includingthecytochromeaa3contentweredeterminedonmitochondriaisolatedbydifferentialcentrifugationandpurifiedbycentrifugationinasucrosedensitygradient.Thegreatestdifferencesinenzymecontentwerefoundbetweenmitochondriaofeggsandthoseofthedifferentiatedtissues.Duringlarvaldevelopmenttherewasonlylittlechangeinthemitochondrialenzymepatternsofliverandtailmuscle.Thegreatestvariationwasfoundinmatrixenzymes,butonlylittlechangewasnotedinthemembrane-boundrespiratoryenzymeSDHandcytochromeaa3whichalsoshowedastrikingcorrelationwiththeamountofinsolublemitochondrialprotein.Byrelatingmitochondrialenzymeactivitiestocytochromeaa3content,tissuespecificactivitypatternswereobtained.Dependinguponthedegreeofvariation,itwaspossibletodifferentiateenzymeswith“constant”and“specificactivityproportions,”eachgroupcomprisingmembrane-boundandmatrixenzymes.Thisindicatesthatenzymecontentmayvaryindependentlyofitspresumedstructuralentityinthemitochondria.

[学科分类] 生物科学（综合）