On the functions of the yeast COX10 and COX11 gene products

Biochem Mol Biol Int. 1993 Nov;31(3):593-8.


COX10 and COX11 are nuclear genes of Saccharomyces cerevisiae whose products are localized in mitochondria and are required for the synthesis of cytochrome oxidase. Genes homologous to COX10 are present in at least four different bacterial cytochrome oxidase operons. The bacterial gene, termed cyoE, has recently been proposed to code for a farnesyl transferase that converts protoheme to heme O (Saiki et al. (1992), Biochem. Biophys. Res. Commun. 189, 1491-1497). In this communication we report that the COX10 protein, like the product of cyoE is needed for heme A synthesis. Analyses of the heme constituents in a cox11 mutant indicate the absence of heme A and presence of a novel heme with chromatographic properties indistinguishable from those of heme O. This evidence suggests that the COX11 protein may be another heme A biosynthetic enzyme involved in forming the formyl group at position 8 of the porphyrin ring.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Alkyl and Aryl Transferases*
  • Amino Acid Sequence
  • Bacteria / genetics
  • Electron Transport Complex IV / metabolism
  • Farnesyltranstransferase
  • Fungal Proteins / genetics
  • Fungal Proteins / physiology*
  • Genes, Fungal*
  • Heme / analogs & derivatives*
  • Heme / biosynthesis
  • Membrane Proteins / genetics
  • Membrane Proteins / physiology*
  • Mitochondria / metabolism*
  • Mitochondrial Proteins
  • Molecular Sequence Data
  • Saccharomyces cerevisiae / genetics*
  • Saccharomyces cerevisiae / physiology
  • Saccharomyces cerevisiae Proteins*
  • Sequence Alignment
  • Sequence Homology, Amino Acid
  • Transferases / chemistry


  • COX11 protein, S cerevisiae
  • Fungal Proteins
  • Membrane Proteins
  • Mitochondrial Proteins
  • Saccharomyces cerevisiae Proteins
  • heme a
  • Heme
  • Electron Transport Complex IV
  • Transferases
  • Alkyl and Aryl Transferases
  • COX10 protein, S cerevisiae
  • Farnesyltranstransferase