TRANSDUCIN GTPASE PROVIDES FOR RAPID QUENCHING OF THE CGMP CASCADE IN ROD OUTER SEGMENTS
TRANSDUCIN GTPASE PROVIDES FOR RAPID QUENCHING OF THE CGMP CASCADE IN ROD OUTER SEGMENTS
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DOI：
10.1016/0014-5793(89)80754-9
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发表时间：
1989-07-03
期刊：
影响因子：
3.5
通讯作者：
PHILIPPOV, PP
中科院分区：
文献类型：
--
作者：
ARSHAVSKY, VY;ANTOCH, MP;PHILIPPOV, PP
在快速cGMP磷酸二酯酶淬灭的作用transducin GTP酶的研究，同时注册的GTP水解和磷酸二酯酶活性在同一杆外节（ROS）的准备。由此获得的结果允许以下结论：（i）磷酸二酯酶淬灭与转导蛋白结合的GTP水解一致，而与ROS浓度无关;（ii）由于ROS中存在GTP酶加速机制，ROS浓度的增加导致级联淬灭的加速;（iii）接近生理条件（蛋白质浓度、温度）提供等于每秒1-2次转换的转导蛋白GT3速率，即，足够高以满足暗适应视杆中光响应回复的真实的速率。
The role of transducin GTPase in rapid cGMP phosphodiesterase quenching was studied by simultaneous registration of GTP hydrolysis and phosphodiesterase activity in the same rod outer segments (ROS) preparation. The results thus obtained allow the conclusion that: (i) phosphodiesterase quenching coincides with transducin‐bound GTP hydrolysis independently of ROS concentration; (ii) an increase in the ROS concentration results in the acceleration of cascade quenching due to the existence of a GTPase accelerating mechanism in ROS; (iii) approximation to physiological conditions (protein concentration, temperature) provides a transducin GTPase rate equal to 1–2 turnovers per second i.e., sufficiently high for satisfying the real rate of photoresponse reversion in dark‐adapted rods.