Open AccessLight‐Induced Absorbance Changes of the High‐Potential Cytochrome b 559 in Chloroplasts
Author(s) -
BenHayyim Gozal
Publication year - 1974
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1974.tb03259.x
Subject(s) - dcmu , photosystem i , photochemistry , cytochrome b6f complex , photosystem ii , p700 , chemistry , cytochrome , electron acceptor , electron transport chain , absorbance , chloroplast , photosynthesis , cytochrome b , biophysics , biology , biochemistry , gene , enzyme , chromatography , mitochondrial dna
1 Light‐induced absorption changes of cytochrome b 559 have been studied in isolated chloroplast preparations at room temperature. 2 It was shown that cytochrome b 559 could undergo both photooxidation and photoreduction, both these reactions occurring to its high‐potential form. 3 In the presence of FCCP and DCMU, a reversible photoreduction could be detected which was not sensitive to the presence of oxygen and which was probably a result of a cyclic electron flow around photosystem 2. 4 It is suggested that the high‐potential form of cytochrome b 559 , which is the native form, is mainly photooxidized by photosystem 2. The photoreduction is also mediated by photosystem 2 and can be detected only when electrons cannot flow from photosystem 2 to photosystem 1, i.e. in the presence of DCMU, or when the carriers are fully reduced in the absence of an electron acceptor.