On the role of transducin GTPase in the quenching of a phosphodiesterase cascade of vision.

Journal Article (Journal Article)

The rate of GTP hydrolysis in the active site of transducin and that of the release of the phosphate thus formed have been measured. The former step has been found to be a rate-limiting one. The rate constant for GTP hydrolysis is equal to 0.027 s-1 at 23 degrees C, and 0.07 s-1 at 37 degrees C. Besides, it has been shown that the rate of GTPase reaction on the transducin alpha-subunit does not depend on the concentration of a complex of transducin beta- and gamma-subunits or on the presence of cGMP phosphodiesterase and a 48 kDa protein from rod outer segments. According to the results, GTP hydrolysis on transducin proceeds too slowly to account for the rapid quenching of a phosphodiesterase cascade in rod outer segments.

Full Text

Duke Authors

Cited Authors

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

Published Date

  • November 16, 1987

Published In

Volume / Issue

  • 224 / 1

Start / End Page

  • 19 - 22

PubMed ID

  • 2824241

International Standard Serial Number (ISSN)

  • 0014-5793

Digital Object Identifier (DOI)

  • 10.1016/0014-5793(87)80414-3


  • eng

Conference Location

  • England