Subunit Composition ofCytochrome c Oxidase in Mitochondria ofZeamays

Cytochrome coxidase hasbeenpurified fromZeamaysmitochondria byasolubilization withdodecyl maltoside followed by asimple andrapid twostepfastprotein liquid chromatographic methodinvolving anionexchange onMonoQ andsizeexclusion chromatography onSuperose 12.Thepreparation obtained was resolved byureasodium dodecyl sulfate-polyacrylamide gelelectrophoresis andhadasubunit composition comprising polypeptides ofapparent molecular massesof48,31,and25kilodaltons atleast oneat16and11kilodaltons andthree subunits below10 kilodaltons. Comparison withapurified yeastcytochrome coxidaserevealed thatthefourlargest subunits showedsimilar electrophoretic mobilities. Subunits Iand11cross-reacted with antibodies raised against theyeasthomologous polypeptides. Polypeptides oftheplant ubiquinone:cytochrome c reductase complex havealsobeenidentified bycross-reaction withantibodies raised against yeastcytochrome bandc1subunits and byinference fromcomigration.