Photooxidation of cytochrome b-559 in leaves and chloroplasts at room temperature

R. G. Hiller, Jan M. Anderson, N. K. Boardman

Research output: Contribution to journalArticleResearchpeer-review

Abstract

1. Light-induced absorbance changes of cytochrome b-559 and cytochrome f in the α-band region were examined in leaves and in isolated chloroplasts. 2. Absorbance changes of cytochrome b-559 were not detected in untreated leaves or in most preparations of isolated chloroplasts. After treatment of leaves or chloroplasts with carbonyl cyanide m-chlorophenylhydrazone, high rates of photooxidation of cytochrome b-559 were obtained, both in far-red (>700 nm) and red actinic light. Cytochrome f was photooxidized in far-red light, but in red light it remained mainly in the reduced state. The initial rates of photooxidation of cytochrome b-559 in leaves or chloroplasts treated with carbonyl cyanide m-chlorophenylhydrazone were considerably decreased by 3-(3′,4′-dichlorophenyl)-1,1-dimethyl urea. 3. A slow photoreduction of cytochrome b-559 was observed in aged mutant pea chloroplasts in red light. 4. The results do not support the view that cytochrome b-559 is a component of the electron transport chain between the light reactions. It is suggested that cytochrome b-559 is located on a side path from Photosystem II, but with a possible additional link to Photosystem I.

Original languageEnglish
Pages (from-to)439-452
Number of pages14
JournalBBA - Bioenergetics
Volume245
Issue number2
DOIs
Publication statusPublished - 7 Sep 1971

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