The facilitated diffusion of ions across cellulose membranes loaded with cytochrome c

Rimona Margalit*, Abel Schejter

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Ferricytochrome c bound to a cellulose membrane facilitates the diffusion of Cl- ions across the membrane, along the electrochemical gradient. Ferrocytochrome c facilitates in a similar fashion the diffusion of Co2+ ions. The observed dependence of the facilitated fluxes on the electrochemical gradient is compatible with cytochrome c acting as a carrier, utilising the specific, reversible, ion binding reaction previously observed in solution. The diffusion coefficients observed for ferri and ferrocytochrome in the membrane media are, respectively, 1.9×10-7 cm2 s-1 and 0.8×10-7 cm2 s-1. A cellulose membrane was the system used for these diffusion studies. Cytochrome c, in both oxidation states, binds to the cellulose membrane with a high affinity. The dissociation constant determined is 4×10-5 M. The association rate is 5×103 M-1 hour-1, and the dissociation rate is 5×10-2 per hour. The membrane-bound protein retains its redox and ion-binding properties. The spectrum of the membrane-bound protein is identical qualitatively and quantitatively to the one of the aqueous soluble protein in the range of 400-600 nm.

Original languageEnglish
Pages (from-to)189-202
Number of pages14
JournalBioelectrochemistry and Bioenergetics
Volume3
Issue number2
DOIs
StatePublished - 1976

Funding

FundersFunder number
BATH-SHEVA de ROTHSCHILD

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