Institute of Biophysics, Biological Research Center, Hungarian Academy of Sciences, P.O. Box 521, H-6701, Szeged, Hungary.
Photosynth Res. 1993 Apr;36(1):59-64. doi: 10.1007/BF00018075.
Flash-induced, fast (t 1/2 ≈ 1 ms), reversible reduction of the high potential cytochrome b-559 (cyt b-559HP) was observed in chloroplasts in the presence of 2 μM protonophore, FCCP (carbonylcyanide p-trifluoromethoxyphenylhydrazone), CCCP (carbonylcyanide 3-chlorophenylhydrazone) or SF 6847 (2,6-di-(t-butyl)-4-(2',2'-dicyanovinyl)phenol). These protonophores promote autooxidation of cyt b-559HP in the dark (Arnon and Tang 1988, Proc Natl Acad Sci USA 85: 9524). No fast photoreduction could, however, be observed if the molecules were oxidized with ferricyanide in the absence of protonophores. This suggests that the molecules must be deprotonated to be capable for fast photoreduction.Photoreduction of cyt b-559HP was largely insensitive to DBMIB (2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone), but was inhibited by DCMU (3-(3,4-dichlorophenyl)-1,1-dimethylurea). With a train of flashes, no oscillation could be observed in the amplitudes of photoreduction. These data strongly suggest that cyt b-559HP is reduced by the semireduced secondary quinone acceptor (QB (-)) of Photosystem 2.
在 2 μM 质子载体 FCCP（羰基氰化物对三氟甲氧基苯腙）、CCCP（羰基氰化物 3-氯苯腙）或 SF 6847（2,6-二叔丁基-4-（2',2'-二氰基乙烯基）苯酚）存在的情况下，观察到叶绿体中高电位细胞色素 b-559（cyt b-559HP）的快速（t 1/2 ≈ 1 ms）、瞬态还原。这些质子载体在黑暗中促进 cyt b-559HP 的自动氧化（Arnon 和 Tang 1988，Proc Natl Acad Sci USA 85: 9524）。然而，如果分子在没有质子载体的情况下用铁氰化物氧化，则无法观察到快速光还原。这表明分子必须去质子化才能进行快速光还原。光还原 cyt b-559HP 对 DBMIB（2,5-二溴-3-甲基-6-异丙基-p-苯醌）的敏感性不大，但被 DCMU（3-(3,4-二氯苯基）-1,1-二甲基脲）抑制。在一系列闪光下，光还原幅度没有观察到振荡。这些数据强烈表明 cyt b-559HP 被光系统 2 的半还原的二次醌受体（QB (-)）还原。
