Kinetic study of isomerization of ferricytochrome c at alkaline pH

Hiroshi Kihara, Satoshi Saigo, Hiroshi Nakatani, Keitaro Hiromi, Masao Ikeda-Saito, Tetsutaro Iizuka

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43 Citations (Scopus)


Kinetic studies of the isomerization reaction of horse heart ferricytochrome c between pH 8.5 and pH 12.1 have been carried out by using stopped-flow and rapid scanning stopped-flow techniques. Below pH 10, our results were in good agreement with the scheme proposed earlier (Davis, L. A., Schejter, A. and Hess, G. P. (1974) J. Biol. Chem. 249, 2624-2632). Above pH 10, another faster first-order process was observed, which suggested the existence of a transient species in the isomerization reaction between the species with and without a 695 nm band. The probable scheme of the isomerization reaction is considered to be {A figure is presented} where H denotes a proton, the colored forms are the species predominant at neutral pH with a 695 nm band and the noncolored forms are the species without a 695 nm band. The transient species has a small 695 nm absorbance which suggests that the sixth ligand is still Met-80, although the protein conformation might be different from that at neutral pH.

Original languageEnglish
Pages (from-to)225-243
Number of pages19
JournalBBA - Bioenergetics
Issue number2
Publication statusPublished - 1976 May 14

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Cell Biology


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