Transducin GTPase provides for rapid quenching of the cGMP cascade in rod outer segments.

Journal Article (Journal Article)

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.

Full Text

Duke Authors

Cited Authors

  • Arshavsky VYu, ; Antoch, MP; Lukjanov, KA; Philippov, PP

Published Date

  • July 3, 1989

Published In

Volume / Issue

  • 250 / 2

Start / End Page

  • 353 - 356

PubMed ID

  • 2546803

International Standard Serial Number (ISSN)

  • 0014-5793

Digital Object Identifier (DOI)

  • 10.1016/0014-5793(89)80754-9


  • eng

Conference Location

  • England