Demonstration of two isoforms of subunit VIIa of cytochrome c oxidase from human skeletal muscle. Implications for mitochondrial myopathies.
Two different isoforms of subunit VIIa have been found in cytochrome c oxidase isolated from human skeletal muscle. The first 22 residues of the N-terminal amino acid sequences showed 5 differences. Our results provide the first conclusive evidence for the existence of cytochrome c oxidase isoenzymes in man. Since the two cytochrome c oxidase isoforms were both present in skeletal muscle tissue, though not necessarily in the same cell type, this suggests that human cytochrome c oxidase isoforms are not strictly tissue-specific. These findings may have important implications for the elucidation of genetic diseases in man in which a deficiency of cytochrome c oxidase is restricted to certain tissues.
Van Beeumen
J J
JJ
Laboratory of Microbiology and Microbial Genetics, University of Gent, Belgium.
Van Kuilenburg
A B
AB
Van Bun
S
S
Van den Bogert
C
C
Tager
J M
JM
Muijsers
A O
AO
D000595:Amino Acid Sequence; D002851:Chromatography, High Pressure Liquid; D003576:Electron Transport Complex IV / Q000302:isolation & purification*; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D007527:Isoenzymes / Q000302:isolation & purification*; D008969:Molecular Sequence Data; D009132:Muscles / Q000201:enzymology*; D009135:Muscular Diseases / Q000201:enzymology
D007527:Isoenzymes; D003576:Electron Transport Complex IV