Heber U, Kirk M R, Boardman N K
Biochim Biophys Acta. 1979 May 9;546(2):292-306. doi: 10.1016/0005-2728(79)90047-1.
The high potential cytochrome b-559 of intact spinach chloroplasts was photooxidized by red light with a high quantum efficiency and by far-red light with a very low quantum efficiency, when electron flow from water to Photosystem II was inhibited by a carbonyl cyanide phenylhydrazone (FCCP or CCP). Dithiothreitol, which reacts with FCCP or CCCP, reversed the photooxidation of cytochrome b-559 and restored the capability of the chloroplasts to photoreduce CO2 showing that the FCCP/CCCP effects were reversible. The quantum efficiency of cytochrome b-559 photooxidation by red or far-red light in the presence of FCCP was increased by 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone which blocks oxidation of reduced plastoquinone by Photosystem I. When the inhibition of water oxidation by FCCP or CCP was decreased by increased light intensities, previously photooxidized cytochrome b-559 was reduced. Red light was much more effective in photoreducing oxidized high potential cytochrome b-559 than far-red light. The red/far-red antagonism in the redox state of cytochrome b-559 is a consequence of the different sensitivity of the cytochrome to red and far-red light and does not indicate that the cytochrome is in the main path of electrons from water to NADP. Rather, cytochrome b-559 acts as a carrier of electrons in a cyclic path around Photosystem II. The redox state of the cytochrome was shifted to the oxidized side when electron transport from water became rate-limiting, while oxidation of water and reduction of plastoquinone resulted in its shifting to the reduced side.
当羰基氰苯腙（FCCP或CCP）抑制从水到光系统II的电子流时，完整菠菜叶绿体中的高电位细胞色素b - 559可被红光以高量子效率光氧化，被远红光以非常低的量子效率光氧化。与FCCP或CCCP反应的二硫苏糖醇可逆转细胞色素b - 559的光氧化，并恢复叶绿体光还原CO2的能力，表明FCCP/CCCP的作用是可逆的。在存在FCCP的情况下，2,5 - 二溴 - 3 - 甲基 - 6 - 异丙基 - 对苯醌可提高红光或远红光对细胞色素b - 559光氧化的量子效率，该醌可阻断光系统I对还原型质体醌的氧化。当通过增加光强降低FCCP或CCP对水氧化的抑制作用时，先前光氧化的细胞色素b - 559会被还原。红光在光还原氧化型高电位细胞色素b - 559方面比远红光有效得多。细胞色素b - 559氧化还原状态中的红/远红拮抗作用是该细胞色素对红光和远红光不同敏感性的结果，并不表明该细胞色素处于从水到NADP的电子主要路径中。相反，细胞色素b - 559在围绕光系统II的循环路径中充当电子载体。当从水的电子传递成为限速步骤时，细胞色素的氧化还原状态会向氧化侧移动，而水的氧化和质体醌的还原会导致其向还原侧移动。
