Mills J D, Crowther D, Slovacek R E, Hind G, McCarty R E
Biochim Biophys Acta. 1979 Jul 10;547(1):127-37. doi: 10.1016/0005-2728(79)90101-4.
Addition of NADPH to osmotically lysed spinach chloroplasts results in a reduction of the primary acceptor (Q) of photosystem II. This reduction of Q reaches a maximum of 50% in chloroplasts maintained under weak illumination and requires added ferredoxin and Mg2+. The reaction is inhibited by (I) an antibody to ferredoxin-NADP+ reductases (EC 1.6.7.1), (ii) treatment of chloroplasts with N-ethylmaleimide in the presence of NADPH, (iii) disulfodisalicylidenepropanediamine, (iv) antimycin, and (v) acceptors of non-cyclic electron transport. Uncouplers of phosphorylation do not affect NADPH-driven reduction of Q. It is proposed that electron flow from NADPH to Q may occur in the dark by a pathway utilising portions of the normal cyclic and non-cyclic electron carrier sequences. The possible in vivo role for such a pathway in redox poising of cyclic electron transport and hence in controlling the ATP/NADPH supply ratio is discussed.
向经渗透裂解的菠菜叶绿体中添加NADPH会导致光系统II的初级受体（Q）被还原。在弱光照下维持的叶绿体中，Q的这种还原作用最高可达50%，并且需要添加铁氧还蛋白和Mg2+。该反应受到以下物质的抑制：（i）抗铁氧还蛋白-NADP+还原酶（EC 1.6.7.1）的抗体；（ii）在NADPH存在的情况下用N-乙基马来酰亚胺处理叶绿体；（iii）二硫代二水杨酸丙二胺；（iv）抗霉素；以及（v）非循环电子传递的受体。磷酸化解偶联剂不影响NADPH驱动的Q还原。有人提出，在黑暗中，电子可能通过利用部分正常循环和非循环电子载体序列的途径从NADPH流向Q。本文讨论了这种途径在循环电子传递的氧化还原平衡中以及因此在控制ATP/NADPH供应比例方面可能在体内发挥的作用。
