[Light-induced redox conversions of cytochrome f in pea leaves]

Redox conversions of cytochrome f were studied in intact pea leaves by double wavelength difference spectrophotometry. Using the inhibition of the photosystem II activity by far red light (719 nm) or diurone, it was found that cytochrome f is located between two photosystems on the oxidative side of photosystem I. The inhibitors of phosphorylation, , e.g. antimycin A and phloridzine, as well as the uncoupler, methylamine, strongly decreased electron transport through the carrier. It is concluded that cytochrome f is functioning in the non-cyclic phosphorylation. It is suggested that in vivo cytochrome f is not coupled with cyclic electron transfer.