Sabat S C, Babu T S, Mohanty P
School of Life Sciences, Jawaharlal Nehru University, New Delhi, India.
Biochem Biophys Res Commun. 1991 Sep 16;179(2):1127-33. doi: 10.1016/0006-291x(91)91937-8.
Diethylhydroxylamine, when added to beet spinach thylakoid membranes in the reaction mixture enhanced both photosystem II mediated dichlorophenolindophenol photoreduction and whole chain electron transport supported by methyl viologen. Diethylhydroxylamine supports dichlorophenolindophenol photoreduction when oxygen evolving complex is inactivated by hydroxylamine washings. All the electron transport assays were found to be highly sensitive to diuron, indicating that diethylhydroxylamine donates electrons to the photosystem II before the herbicide binding site. The stimulation of the photochemical activity by diethylhydroxylamine is not solely due to its action as an uncoupler. It was also observed that the action of diethylhydroxylamine was not altered by preincubations of thylakoids in light in the presence of diethylhydroxylamine. Also, thylakoid membranes did not lose their benzoquinone Hill activity by the pre-incubations with diethylhydroxylamine either in light or in dark. Thus, unlike the photosystem II electron donor, hydroxylamine, diethylhydroxylamine was found to donate electrons without the inactivations of oxygen evolving complex. It is suggested that diethylhydroxylamine is a useful electron donor to the photosystem II.
当将二乙羟胺添加到反应混合物中的甜菜菠菜类囊体膜时，它增强了光系统II介导的二氯酚靛酚光还原作用以及由甲基紫精支持的全链电子传递。当通过羟胺洗涤使放氧复合体失活时，二乙羟胺支持二氯酚靛酚光还原作用。发现所有电子传递测定对敌草隆高度敏感，这表明二乙羟胺在除草剂结合位点之前就向光系统II供电子。二乙羟胺对光化学活性的刺激不仅仅是由于其作为解偶联剂的作用。还观察到，在二乙羟胺存在下，类囊体在光照下预孵育不会改变二乙羟胺的作用。此外，类囊体膜在光照或黑暗中与二乙羟胺预孵育后，也不会丧失其苯醌希尔活性。因此，与光系统II电子供体羟胺不同，发现二乙羟胺供电子时不会使放氧复合体失活。有人提出，二乙羟胺是光系统II的一种有用电子供体。
