Constitutive activity of Sauromatum guttatum alternative oxidase in Schizosaccharomyces pombe implicates residues in addition to conserved cysteines in α-keto acid activation

Paul G. Crichton, Charles Affourtit, Mary S. Albury, Jane E. Carré, Anthony L. Moore

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39 Citations (Scopus)


Activity of the plant mitochondrial alternative oxidase (AOX) can be regulated by organic acids, notably pyruvate. To date, only two well-conserved cysteine residues have been implicated in this process. We report the functional expression of two AOX isozymes (Sauromatum guttatum Sg-AOX and Arabidopsis thaliana At-AOX1a) in Schizosaccharomyces pombe. Comparison of the response of these two isozymes to pyruvate in isolated yeast mitochondria and disrupted mitochondrial membranes reveals that in contrast to At-AOX1a, Sg-AOX activity is insensitive to pyruvate and appears to be in a constitutively active state. As both of these isozymes conserve the two cysteines, we propose that such contrasting behaviour must be a direct result of differences in their amino acid sequence and have subsequently identified novel candidate residues.

Original languageEnglish
Pages (from-to)331-336
Number of pages6
JournalFEBS Letters
Issue number2
Early online date8 Dec 2004
Publication statusPublished - 17 Jan 2005


  • CCP
  • carbonyl cyanide m-chlorophenylhydrazone
  • Q(H2)
  • ubiquinone/ubiquinol
  • Alternative oxidase structure
  • Regulation
  • Pyruvate
  • Plant respiration
  • S. pombe mitochondria

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