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. 1973 Jun;70(6):1701–1703. doi: 10.1073/pnas.70.6.1701

Reduction of Ferricytochrome c by Dithionite Ion: Electron Transfer by Parallel Adjacent and Remote Pathways*

Carol Creutz 1, Norman Sutin 1,†
PMCID: PMC433576  PMID: 4352650

Abstract

The kinetics of the reduction of horseheart ferricytochrome c by sodium dithionite (phosphate buffer-sodium chloride; pH 6.5, μ = 1.0, 25°) features two reaction pathways; one with the rate constant k3 = 1.17 × 104 M-1 sec-1, the other with the rate constant k1k2/k-1 = 6.0 × 104 M-1 sec-1. These pathways are interpreted in terms of remote attack (possibly by way of the exposed edge of the porphyrin system) and adjacent attack (requiring the opening of the heme crevice). The limiting rate for the adjacent pathway (k1 = 30 sec-1) is in good agreement with the rate of heme-crevice opening of ferricytochrome c determined in other studies. The implication of the adjacent attack pathway to the function of cytochrome c in vivo is discussed.

Keywords: horse-heart cytochrome c, stopped flow, kinetics, mechanism

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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