title: Identification of tissue-specific isoforms for subunits Vb and VIIa of cytochrome c oxidase isolated from rainbow trout.
abstract: Cytochrome c oxidase was isolated from heart and liver of rainbow trout (Salmo gairdnerii). SDS/PAGE analysis showed the presence of 11 different polypeptide subunits in the fish enzyme. The nuclear-coded subunits IV, Va, Vb, VIc, VIIa, VIIc and VIII could be identified by their N-terminal amino acid sequences. The mammalian subunits VIa and VIIb appear to be absent (or blocked at the N-terminal) in cytochrome c oxidase from trout. For subunit Vb, two polypeptides of different electrophoretic mobilities were found which differed in their N-terminal sequences, and represent a new pair of cytochrome-c-oxidase subunit isoforms, not found in mammalia. Both isoforms of subunit Vb were found in cytochrome c oxidase from heart and liver, but at different ratios. Subunit VIIa also seemed to occur in different isoforms, whereas subunit VIII had the same N-terminal amino acid sequence in cytochrome c oxidase of liver and heart, similar to the human-type subunit but different from rat, bovine and chicken.
authors.affiliation: Fachbereich Chemie der Philipps-Universität, Marburg, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Freund
authors.forename: B
authors.initials: B
authors.lastname: Kadenbach
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003720:Densitometry; D003576:Electron Transport Complex IV / Q000737:chemistry* / Q000302:isolation & purification; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D008322:Mammals; D008929:Mitochondria, Heart / Q000201:enzymology*; D008930:Mitochondria, Liver / Q000201:enzymology*; D008969:Molecular Sequence Data; D017686:Oncorhynchus mykiss; D017386:Sequence Homology, Amino Acid
chemical_list: D003576:Electron Transport Complex IV