A cytochrome f/b6 complex of five polypeptides with plastoquinol-plastocyanin-oxidoreductase activity from spinach chloroplasts

Eur J Biochem. 1981 Jul;117(3):591-5. doi: 10.1111/j.1432-1033.1981.tb06379.x.


The isolation of a cytochrome f/b6 complex from spinach chloroplasts, with high yield and purity is reported. The complex consists of five polypeptides with a molecular mass of 34, 33, 23.5, 20 and 17.5 kDa, and contains one cytochrome f, two cytochromes b6 and the Rieske Fe-S center with two non-heme irons. It does not contain plastocyanin and is almost completely devoid of chlorophyll and carotenoids, but lipid and detergent are present. It is lacking cytochrome b-559, although three of the five polypeptides seem to carry heme groups. The preparation has plastoquinol-plastocyanin oxidoreductase activity with plastoquinol-1 and plastoquinol-9, which is sensitive to 2,5-dibromomethylisopropyl-p-benzoquinone, to 2-iodo-6-isopropyl-3-methyl-2',4',4'-trinitrodiphenyl ether, to 5-n-undecyl-6-hydroxy-4,7-dioxobenzothiazole, and to bathophenanthroline. Characteristics of this activity with respect to substrate concentrations, pH, detergent effect and other parameters are described.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chloroplasts / metabolism*
  • Cytochromes / isolation & purification
  • Cytochromes / metabolism*
  • Cytochromes f
  • Detergents / pharmacology
  • Electron Spin Resonance Spectroscopy
  • Kinetics
  • Macromolecular Substances
  • Molecular Weight
  • Octoxynol
  • Oxidation-Reduction
  • Oxidoreductases / isolation & purification
  • Oxidoreductases / metabolism*
  • Plants / metabolism
  • Polyethylene Glycols / pharmacology


  • Cytochromes
  • Detergents
  • Macromolecular Substances
  • Polyethylene Glycols
  • Octoxynol
  • Cytochromes f
  • Oxidoreductases