THERMAL DECAY OF INTERMEDIATES OF RHODOPSIN IN SITU
THERMAL DECAY OF INTERMEDIATES OF RHODOPSIN IN SITU
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DOI：
10.1016/0042-6989(68)90071-0
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发表时间：
1968-01-01
期刊：
影响因子：
1.8
通讯作者：
EBREY, TG
中科院分区：
文献类型：
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作者：
EBREY, TG
利用光对这些中间体的作用产生的快速光电压，在白化大鼠的视网膜中研究了视紫红质漂白过程中形成的几种中间体的热衰变半衰期。已在一定温度范围内测量了中间体“A”（meta I）、中间体“B”（meta II）和中间体“C”（P465）的衰变速率并计算了它们的动力学参数。这些中间体在 37°C 下的半衰期分别为 40 微秒、140 秒和 1100 秒。只有中间“A”的衰变在生理温度下足够快，才可能参与视觉兴奋。中间“C”的衰变足够慢，可能会影响视紫红质的再生速率。这些原位研究的动力学（伪热力学）参数，例如三种中间体的活化能 ΔF*、ΔH* 和 ΔS*，在实验误差范围内与溶液数据报告的大多数值一致。还使用视紫红质的快速光电压测量了中间体“A”光反转至视紫红质的量子效率，结果为 0.55 ± 0.1。
The half-lives for the thermal decay of several of the intermediates formed in the bleaching of rhodopsin have been studied in the retina of the albino rat using the fast photo voltages produced by the action of light on these intermediates. The rates of decay of Intermediate “A” (meta I), Intermediate “B” (meta II), and Intermediate “C” (P465) have been measured over a range of temperatures and their kinetic parameters calculated. The half-lives of these intermediates at 37°C are 40 microseconds, 140 seconds, and 1100 seconds respectively. Only the decay of Intermediate “A” is rapid enough at physiological temperatures to be possibly involved in visual excitation. The decay of Intermediate “C” is sufficiently slow to perhaps affect the rate of regeneration of rhodopsin. The kinetic (pseudothermodynamic) parameters of thesein situstudies, such as the activation energies, ΔF*, ΔH*and ΔS*for the three intermediates, are in agreement, within experimental error, with most of the values reported from the solution data. The quantum efficiency for the photoreversal of Intermediate “A” to rhodopsin was also measured using the fast photo voltages from rhodopsin and was found to be 0.55 ± 0.1.