Cytochrome c Potentiates Fatty Acid-Induced Cyclosporin A-Sensitive Permeability Transition in Liver Mitochondria

Z. G. Amerkhanov^1,2 and E. N. Mokhova³

¹Institute for Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, 142292 Russia; E-mail: amerkhanov@venus.iteb.serpukhov.su

²To whom correspondence should be addressed.

³Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119899 Russia; E-mail: moch@energ.genebee.msu.su

Submitted June 6, 1997; revision submitted July 1, 1997.

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Addition of 0.5-5 µM cytochrome c and 30 µM lauric acid to rat liver mitochondria stimulated the respiration rate. Stimulation of respiration by cytochrome c was prevented by cyclosporin A and was not observed in the absence of lauric acid. High amplitude swelling of mitochondria in the presence of lauric acid was also potentiated by cytochrome c; this effect was prevented by cyclosporin A or by EGTA. Polylysine (0.35 µM) induced cyclosporin A-insensitive high amplitude swelling of mitochondria. Polylysine-induced swelling was stimulated by lauric acid and cytochrome c; the effect was prevented by cyclosporin A. Incubation of mitochondria with 30 µM lauric acid resulted in an increase in cytochrome c concentration in the incubation medium. Added cytochrome c is supposed to potentiate the laurate-induced cyclosporin A-sensitive permeability transition in cytochrome c-depleted mitochondria.

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KEY WORDS: cytochrome c, fatty acids, polylysine, cyclosporin A-sensitive pore, liver mitochondria.

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