The control of phosphodiesterase in rod disk membranes: Kinetics, possible mechanisms and significance for vision
The control of phosphodiesterase in rod disk membranes: Kinetics, possible mechanisms and significance for vision
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视杆盘膜中磷酸二酯酶的控制：动力学、可能的机制以及对视觉的意义
DOI：
10.1016/0042-6989(79)90097-x
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发表时间：
1979
期刊：
影响因子：
1.8
通讯作者：
E. Pugh
中科院分区：
文献类型：
--
作者：
P. Liebman;E. Pugh
过去七年见证了视觉传导和适应机制的思维和研究中最令人兴奋的转变。我们已经从一个很长的时代，我们的注意力集中在受体中视色素分子的主要数量及其漂白时的光谱变化，到了少数分子湿生物化学的时代。后者的开始引入了Ca”假说（Hagins，1972），同时重要的发现是光能够间接调节控制视紫红质磷酸化的核苷磷酸酶的行为（Kuhn，Cook和Dreyer。1973：Bownds，Dawes。Miller和Stahlman，1972）和其他蛋白质的磷酸化（Bitensky，Gorman和Miller， 1971 年：Bitensky、IMiki、Keirns、Keirns、Baraban、Freeman、Wheeler、Lacy 和 Marcus，1975）。同样重要的是关注转导和适应的定量方面，即所需的扩增规范（Yoshikami 和 Hagins，1973）和速度（Penn 和 Hagins，1972；Baylor、Hodgkin 和 Lamb，1974）。几年前，像其他实验室一样，我们开始寻找实验证据，证明 Ca2+ 可能以足够的数量和足够的速度释放，以验证 CaZc 假设。我们使用稳态和动力学方法。后者使用 Ca'* 敏感金属变色指示剂染料。阿塞纳佐三世尽管我们发现杆中含有的 Ca* i 总量与 Ca’ 假说的定量需求一致（Liebman，1974），但在测量之前我们非常小心地排除可见光的实验始终未能证明光诱导的 Ca2+释放显着（Liebman.1978）。为了将 Ca2+ 重新加载到可能泄漏到 CaZC 的杆盘囊泡中，我们添加了多种能量提供化合物，包括 ATP 和循环”。这些既没有提供支持 Ca”泵存在的证据，也没有提供随后的光介导释放的证据（Liebman，1978）。然而，在光和 ATP 存在的情况下添加环 GMP (cGMP) 在胂 III 测量中产生了剧烈的响应，这被证明是由与 cGMP 快速水解相关的质子引起的，即 Hz0+ cGMP-’= 5’GMP-’+ H’(Liebman 1978)。虽然失败了
The past seven years have witnessed a most exciting transition in thinking and research into the mechanism of visual transduction and adaptation. We have moved from a very long era where our attention was glued to the dominating quantity of visual pigment molecules in the receptors and their spectral changes upon bleaching to an era of minority-molecule wet biochemistry. The beginning of the latter saw introduction of the Ca” hypothesis (Hagins, 1972) and at the same time the important discoveries that light is able to indirectly modulate the behavior of nucleoside phosphate enzymes that control rhodopsin phosphorylation (Kuhn, Cook and Dreyer. 1973: Bownds, Dawes. Miller and Stahlman, 1972) and the phosphorylation of other proteins (Bitensky, Gorman and Miller, 1971: Bitensky, IMiki, Keirns, Keirns, Baraban, Freeman. Wheeler, Lacy and Marcus, 1975). Important also has been the focusing of attention upon the quantitative aspects of transduction and adaptation, ie specification of amplification (Yoshikami and Hagins. 1973) and speed (Penn and Hagins, 1972; Baylor, Hodgkin and Lamb, 1974) required of any model seeking to explain these properties of visual receptors.Several years ago, like other laboratories, we began to seek experimental evidence that Ca” might be released in sufficient quantity and with sufficient speed to verify the CaZc hypothesis. We used both steady-state and kinetic approaches. the latter by using the Ca’* sensitive metalochromic indicator dye. Arsenazo III. Though we found rods to contain Ca* i in total amount consistent with the quantitative needs of the Ca’-hypothsis (Liebman, 1974), experiments in which we were very careful to exclude visible light before measurement consistently failed to demonstrate significant light-induced release of Ca”(Liebman. 1978). In the hope of reloading Ca” into rod disk vesicles that might be leaky to CaZC, we added a variety of energy providing compounds including ATP and cyclic nucleotides in the presence of Ca”. These provided neither evidence favoring presence of a Ca” pump nor subsequent light-mediated release (Liebman, 1978). However, addition of cyclic GMP (cGMP) in the presence of light and ATP produced a dramatic response in the Arsenazo III measurement that proved to be caused by protons associated with rapid hydrolysis of the cGMP, ie Hz0+ cGMP-’= 5’GMP-’+ H’(Liebman 1978). Though failing