Photoreduction of pheophytin at the reaction centres of photosystem II of intact cells of green algae and cyanobacteria in anaerobic conditions

Suleyman Allakhverdiev, V. V. Klimov, V. G. Ladygin

Research output: Contribution to journalArticle


The reversible photoreduction of pheophytin (Pheo) has been detected; it is accompanied by fall in the yield of fluorescence of chlorophyll, in photosystem II of the intact cells of green algae and cyanobacteria in anaerobic conditions. It is shown that this photoreaction is inhibited by diurone and reactivated on subsequent addition of ascorbate or dithionite. It is assumed that donation of an electron from the system of oxidation of water present in the S3 state to the reaction centre of system II in the {A figure is presented}Q- state after the primary photoreaction results in the formation of a longlived state [P680Pheo{A figure is presented}]Q-. It was found that oxidized NADP, benzyl viologen and methyl viologen speed up oxidation of Pheo reduced in the light indicating the ability of these electron acceptors, typical of photosystem I, to accept an electron from Pheo{A figure is presented} in the photosystem II.

Original languageEnglish
Pages (from-to)474-480
Number of pages7
Issue number3
Publication statusPublished - Dec 1 1988
Externally publishedYes


ASJC Scopus subject areas

  • Biophysics

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