A new spectral intermediate in cyanide binding with the oxidized cytochrome c oxidase

Vladimir Berka, Tatiana Vygodina, Andrey Musatov, P. Nicholls, Alexander A. Konstantmov

Research output: Contribution to journalArticlepeer-review

19 Scopus citations


Reaction of cyanide with oxidized cytochrome c oxidase at a low concentration of the ligand and pH > 8 reveals an initial phase, not reported earlier, associated with a small blue shift of the absorption spectrum, which is followed by a conventional red shift of the heme a33+. The initial blue shift resembles the spectral changes induced under the same conditions by low concentrations of azide and it is not observed in the presence of 0.3 mM azide. It is suggested that, similarly to NO, cyanide and HN3 cannot only bind to heme a3 but to Cu2+B as well, perturbing the spectrum of a3+3 indirectly. A rapid binding to Cu2+B could provide the long-sought intermediate in the cyanide reaction with heme a3+3, the existence of which is implied by the Michaelis-Menten type kinetics of the latter process.

Original languageEnglish (US)
Pages (from-to)237-241
Number of pages5
JournalFEBS Letters
Issue number3
StatePublished - Jan 11 1993
Externally publishedYes


  • Azide
  • Cu
  • Cyanide
  • Cytochrome c oxidase
  • Ligand binding
  • Respiratory chain

ASJC Scopus subject areas

  • Biophysics
  • Structural Biology
  • Biochemistry
  • Molecular Biology
  • Genetics
  • Cell Biology


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