Open AccessCytochrome b of Isolated Chloroplasts
Author(s) -
Hayyim Gozal,
Avron Mordhay
Publication year - 1970
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1970.tb00279.x
Subject(s) - cytochrome b6f complex , cytochrome , cytochrome b , electron transport chain , cytochrome c1 , cytochrome c , photosystem i , chemistry , photosystem , photochemistry , cytochrome f , photosystem ii , absorbance , coenzyme q – cytochrome c reductase , biochemistry , photosynthesis , mitochondrion , enzyme , chromatography , mitochondrial dna , gene
1 Cytochrome composition and light‐induced absorbance changes of cytochromes b and f in isolated chloroplasts have been measured in the α‐band region utilizing dual‐wavelength spectrophotometry. Three cytochromes appeared in reduced minus oxidized spectra, whereas only two of them, namely, cytochrome f and a cytochrome b appeared in light‐induced difference spectra. 2 Light‐induced changes of cytochrome b and cytochrome f , indicated that both are located in the part of the electron transport chain joining the two photosystems. The following sequence is supported by the evidence presented: Photosystem 2 → cytochrome b → cytochrome f → photosystem 1. 3 3‐(3,4‐Dichlorophenyl)‐1,1‐dimethyl urea was found to act in the region between photosystem 2 and cytochrome b since the photoinduced oxidation of both cytochromes but not of their reduction were observed in its presence. 4 A site for ATP formation is suggested to be localized in the same region, since in the light the presence of uncouplers or photophosphorylating reagents induced a more reduced steady‐state of both cytochromes.