Voltammetric detection of superoxide production by photosystem II

FEBS Letters

Cleland, Robyn E.²  Grace, Stephen C.¹ 

[1] Biodynamics Institute, 711 Choppin Hall, Louisiana State University, Baton Rouge, LA 70803-1800, USA;Photobioenergetics Group, Research School of Biological Sciences, Australian National University, G.P.O. Box 475, Canberra, ACT 2601, Australia

关键词: Superoxide;    Thylakoid;    Photosystem II;    Mehler reaction;    Quinone;    cyt bf;    cytochrome bf complex;    DCMU;    3-(3;    4-dichlorophenyl)-1;    1-dimethyl urea;    DNP-INT;    2-iodo-2′;    4′;    4′-trinitro-3-methyl-6-isopropyl diphenyl ether;    MV;    methyl viologen;    PQ;    plastoquinone 9;    PSI-sox;    superoxide produced by photosystem I;    PSII-sox;    superoxide produced by photosystem II;    QA;    primary quinone electron acceptor of PSII;    QB;    secondary quinone electron acceptor of PSII;    Qi;    quinone reducing site on cyt bf complex;    Qo;    quinol oxidizing site on cyt bf complex;    SOD;    superoxide dismutase;   

DOI  :  10.1016/S0014-5793(99)01067-4

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Oxygen radicals play both pathological and physiological roles in biological systems. The detection of such radicals is difficult due to their transient nature and the presence of highly efficient antioxidant mechanisms. In plants the physiological role of oxygen is twofold, oxygen is produced by the oxidation of water and consumed as an electron acceptor. The direct involvement of oxygen in photosynthetic events exposes the photosynthetic apparatus to a high probability of damage by oxygen radicals. We report here a direct, simple and rapid method for the measurement of superoxide in vitro based on voltammetric detection. It has potential applications for other in vitro systems investigating superoxide production. We show that in addition to the well established production of superoxide from photosystem I, under reducing conditions superoxide is also produced by photosystem II, probably from the Q_A site.

【 授权许可】

Unknown