Broyde S B, Brody S S
Biophys J. 1966 May;6(3):353-66. doi: 10.1016/s0006-3495(66)86661-4.
A chlorophyll type pigment (F698) fluorescing maximally at 698 mmu at 77 degrees K has been observed in preparations of chlorophyll. This fluorescence is quenched by small amounts of naturally occurring materials, including plastoquinone and the ubiquinones, and by nitrobenzene, probably by formation of a nonfluorescent complex. Fluorescence quenching does not occur in the presence of carotenes, xanthophylls, or reduced plastoquinone and ubiquinone. The fluorescence is sharply temperature dependent, with a steep rise in intensity occurring at 165 degrees K. At 77 degrees K the fluorescence yield is between 0.8 and 1.0. The red absorption maximum of the pigment is at 675 mmu at room temperature and at 688 mmu at 77 degrees K. In vivo, a low temperature emission is also observed at 698 mmu, and this fluorescence is quenched by nitrobenzene. It is proposed that the pigment found in vitro is also the one responsible for emission at 698 mmu in vivo. A reaction of F698 with plastoquinone is suggested as the primary photochemical step in system II of photosynthesis.
在叶绿素制剂中观察到一种叶绿素类色素（F698），在77K时于698毫微米处有最大荧光发射。这种荧光会被少量天然存在的物质淬灭，包括质体醌和泛醌，以及被硝基苯淬灭，可能是通过形成一种无荧光的复合物。在存在胡萝卜素、叶黄素或还原型质体醌和泛醌的情况下不会发生荧光淬灭。这种荧光强烈依赖温度，在165K时强度急剧上升。在77K时荧光产率在0.8到1.0之间。该色素在室温下的最大吸收峰在675毫微米，在77K时在688毫微米。在体内，在698毫微米处也观察到低温发射，并且这种荧光会被硝基苯淬灭。有人提出，在体外发现的这种色素也是体内698毫微米处发射的原因。F698与质体醌的反应被认为是光合作用系统II中的初级光化学步骤。
