Oxygen evolution from hydrogen peroxide in photosystem II: flash-induced catalytic activity of water-oxidizing photosystem II membranes
Oxygen evolution from hydrogen peroxide in photosystem II: flash-induced catalytic activity of water-oxidizing photosystem II membranes
复制标题
光系统 II 中过氧化氢的析氧：水氧化光系统 II 膜的闪光诱导催化活性
DOI：
10.1021/bi00383a014
复制
发表时间：
1987
期刊：
影响因子：
2.9
通讯作者：
K. Asada
中科院分区：
文献类型：
--
作者：
J. Mano;M. Takahashi;K. Asada
在黑暗中用过氧化氢处理的水氧化光系统(PS)II膜表现出从S/亚0/态向S/亚1/态的反向跃迁，这是由闪光-氧气产生模式推断的。在过氧化氢存在的情况下，它们在第一次闪光后放出氧气，就像报道的类囊体体一样。作者使用了H/sub2//sup 18/O/sub2/和一个质谱仪，可以监测介质中的氧同位素，以确定闪光产额。PS II膜在H/sub2//sup 18/O/sub2/1 mm以下演化为/sup 18/O/sub2/和/sup 16/O/sub2/，但在1 mm以上演化的/sup 16/O/sub2/很少。NO/SUP 16/O/SUP 18/O在任何条件下进化。在较高浓度下，过氧化氢的产氧量是PS II反应中心的20多倍，闪蒸后放氧的衰减速度比水慢得多。通过缩短闪光之间的暗间隔，/sup 18/O/sub2/的进化减少，而/sup 16/O/sub2/的进化增加。Little/sup 18/O/sub2/在连续光照下进化。PSⅡ膜中H_2O_2从H_2O_2闪光诱导放出是因为假设更多的假设是：S/SUB_0//S/SUB_2/态循环具有缓慢的催化活性，而这种活性的丧失是由于S/SUB_0/到S/亚_1/态，S/亚_2/到S/亚_1/态，以及S/亚_2/在光作用下推进到S/亚_3/态。PS II膜的三(羟甲基)氨基甲烷(Tris)处理降低了氧气的产量，并消除了过氧化氢催化合成氧气的动力学特征。
Water-oxidizing photosystem (PS) II membranes treated with hydrogen peroxide in the dark showed backward transition of their S/sub 0/ state to the S/sub -1/ state, as deduced from the pattern of flash-dioxygen yields. In the presence of hydrogen peroxide, they evolved oxygen after the first flash, as reported for thylakoids. The authors used H/sub 2/ /sup 18/O/sub 2/ and a mass spectrometer that allowed monitoring of the oxygen isotopes in the medium to determine the flash yields. PS II membranes evolved /sup 18/O/sub 2/ and /sup 16/O/sub 2/ in H/sub 2/ /sup 18/O/sub 2/ below 1 mM, but little /sup 16/O/sub 2/ was evolved above 1 mM. No /sup 16/O/sup 18/O was evolved under any conditions. The oxygen yields from hydrogen peroxide at higher concentrations were more than 20-fold that for the PS II reaction center, and the decay of oxygen evolution after the flash was much slower than that from water. By shortening the dark interval between flashes, the evolution of /sup 18/O/sub 2/ was decreased and that of /sup 16/O/sub 2/ increased. Little /sup 18/O/sub 2/ was evolved under continuous light. The flash-induced evolution of dioxygen from hydrogen peroxide in PS II membranes is inferred from the assumptionmore » that the S/sub 0//S/sub 2/-state cycle has catalatic activity with a slow rate and that this activity is lost by the reduction of S/sub 0/ to the S/sub -1/ state, the spontaneous decay of S/sub 2/ to the S/sub 1/ state, and the advancement of S/sub 2/ to the S/sub 3/ state by light. Tris(hydroxymethyl)aminomethane (Tris) treatment of PS II membranes decreased the yield of dioxygen and extinguished the kinetic features that characterize the catalatic production of dioxygen from hydrogen peroxide.« less