Kinetics of the electrogenic step and cytochrome b 6 and f redox changes in chloroplasts

FEBS Letters

Selak, M.A.¹  Whitmarsh, J.¹ 

[1] Department of Botany, USDA/ARS, University of Illinois, Urbana ILL 61801, USA

关键词: Photosynthesis;    Non-cyclic electron transport;    Q cycle;    Cytochrome b 6;    Cytochrome f;    Electrochromic;    DBMIB;    2;    5-dibromo-3-methyl-6-isopropyl-p-benzoquinone;    DCMU;    3-(3;    4-dichlorophenyl)-1;    1-dimethylurea;    DNP-INT;    2-iodo-6-isopropyl-3-methyl-2′;    4;    4′-trinitrodiphenyl ether;    HQNO;    2-heptyl-4-hydroxyquinoline N-oxide;    PS;    photosystem;    UHDBT;    5-(n-undecyl)-6-hydroxy-4;    7-dioxobenzothiazole;   

DOI  :  10.1016/0014-5793(82)80753-9

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The spectroscopic measurements of the slow phase of the electrochromic effect and the redox kinetics of cytochrome b ₆ and f provide strong evidence that a Q cycle operates in chloroplasts under conditions of non-cyclic electron transport. The effect of HQNO and DBMIB on the extent and kinetics of these light-induced changes places several constraints on the mechanism of quinol oxidation by the cyt. b/f—FeS complex: for each electron removed from the cyt. b/f—FeS complex by P700 an additional charge is transferred across the membrane; the cyclic pathway of electrons involved in quinol oxidation by the cyt. b/f—FeS complex includes at least one of the two b₆ cytochromes; the electrogenic step associated with quinol oxidation is subsequent to the reduction of at least one cytochrome b₆ quinol oxidation may proceed in a stepwise manner, with the first electron going to cytochrome b₆ and the second electron going to the FeS center and cytochrome f.

【 授权许可】

Unknown