Flavocytochrome C of Chromatium Vinosum. Some Enzymatic Properties and Subunit Structure

J Biochem. 1979 Jun;85(6):1405-14. doi: 10.1093/oxfordjournals.jbchem.a132467.

Abstract

The function and the structural features of Chromatium vinosum cytochrome c-552 have been investigated. Cytochrome c-552 has a sulfide-cytochrome c reductase activity and also catalyzes the reduction of elementary sulfur to sulfide with reduced benzylviologen as the electron donor. In the sulfide-cytochrome reduction, horse and yeast cytochromes c act as good electron acceptors, but cytochrome c' or cytochrome c-553(550) purified from the organism does not. The subunit structure of cytochrome c-552 has been studied. The cytochrome is split by 6 M urea into cytochrome and flavoprotein moieties with molecular weights of 21,000 and 46,000, respectively. The flavoprotein moiety is obtained by isoelectric focusing in the presence of 6 M urea and 0.1% beta-mercaptoethanol, while the hemoprotein moiety is obtained by gel filtration with Sephacryl S-200 in the presence of 6 M urea and 0.1 M KCl. Neither subunit has sulfide-cytochrome c reductase activity. Attempts to reconstitute the original flavocytochrome c from the subunits have been unsuccessful.

MeSH terms

  • Amino Acids / analysis
  • Animals
  • Chromatium / metabolism*
  • Cyanides / pharmacology
  • Cytochrome c Group* / metabolism
  • Horses
  • Kinetics
  • Macromolecular Substances
  • Molecular Weight
  • Species Specificity
  • Spectrophotometry

Substances

  • Amino Acids
  • Cyanides
  • Cytochrome c Group
  • Macromolecular Substances