Kühn H
Nature. 1980 Feb 7;283(5747):587-9. doi: 10.1038/283587a0.
Light absorption by photoreceptor rod outer segments (ROS) leads not only to spectral and structural changes in the rhodopsin molecule but also to the activation of several enzymatic activities including GTPase. The mechanism of this effect is not known; however, in all cases where the action spectrum of light-induced enzyme activation has been measured (see, for example, refs 4, 8), it matched the absorption spectrum of rhodopsin. This suggests that bleaching of rhodopsin is the primary step in enzyme activation, and that some light-induced changes in the molecular interaction of the enzymes with rhodopsin, the major intrinsic ROS membrane protein, should be involved. I have indeed found that light induces profound changes in the interation of rhodopsin kinase, GTPase (reported here), and other proteins with the photoreceptor membrane. These changes are reversible in the dark, are strongly influenced by GTP, and are thought to be involved in the regulation of enzyme activity by light. The light-induced binding of the GTPase and its subsequent elution with GTP was used to purify this enzyme.
光感受器视杆细胞外段（ROS）对光的吸收不仅会导致视紫红质分子发生光谱和结构变化，还会激活包括GTP酶在内的多种酶活性。这种效应的机制尚不清楚；然而，在所有已测量光诱导酶激活作用光谱的情况下（例如，见参考文献4、8），它都与视紫红质的吸收光谱相匹配。这表明视紫红质的漂白是酶激活的首要步骤，并且应该涉及到光诱导的酶与视紫红质（ROS主要内在膜蛋白）分子相互作用的一些变化。我确实发现光会引起视紫红质激酶、GTP酶（本文报道）以及其他蛋白质与光感受器膜相互作用的深刻变化。这些变化在黑暗中是可逆的，受到GTP的强烈影响，并且被认为与光对酶活性的调节有关。利用光诱导的GTP酶结合及其随后用GTP洗脱的方法来纯化这种酶。
