Maleimides stimulate oxygen reduction in illuminated thylakoids.
N-ethylmaleimide (NEM) and N,N'-(1,4-phenylene)dimaleimide (PDM) were discovered to stimulate light-induced oxygen uptake in isolated thylakoids, and PDM provided the same stimulation at one order less concentrations. Oxygen uptake rate increased promptly after NEM or PDM addition to thylakoids. The inhibitors of photosynthetic electron transport as well as catalase decreased this rate close to zero, whereas ascorbate increased it almost three-fold. Dithiothreitol suppressed oxygen uptake stimulated by NEM. NEM stimulated light-induced reduction of cytochrome c, and this stimulation was suppressed by superoxide dismutase. It was concluded that NEM and PDM being reduced can effectively reduce molecules O(2) producing superoxide radicals.
Ivanov
Boris
B
Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino 142290, Russia. ivabor@iname.com
Ignat'ev
Alexander
A
Khorobrykh
Sergey
S
D004229:Dithiothreitol / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004579:Electron Transport; D005033:Ethylmaleimide / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D007700:Kinetics; D008027:Light; D008301:Maleimides / Q000494:pharmacology*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption; D013481:Superoxides / Q000378:metabolism; D020524:Thylakoids / Q000187:drug effects / Q000378:metabolism*
D008301:Maleimides; D013481:Superoxides; C011328:N,N'-4-phenylenedimaleimide; D005033:Ethylmaleimide; D010100:Oxygen; D004229:Dithiothreitol