Characteristics of 5'-guanylyl imidodiphosphate-activated adenylate cyclase.

Journal Article (Journal Article)

Characteristics of adenylate cyclase stimulation by the GTP analog 5'-guanyl imidodiphosphate Gpp(NH)p have been examined in intact frog erythrocytes, frog erythrocyte membranes, and solubilized canine myocardial preparations. Gpp(NH)p caused marked enzyme activation in the erythrocyte membranes and in solubilized myocardial preparations, but had much lesser effects in intact cells. Enzyme activation by Gpp(NH)p exhibited a definite lag period, requiring 10 to 15 min for complete activation at 37 degrees. Activation was essentially irreversible after a 5-hour dialysis sufficient to reduce the Gpp(NH)p levels below threshold for stimulation. Gpp(NH)p-"activated" enzyme differed from native enzyme in several respects, such as its greater temperature stability, and its insensitivity to further stimulation by other activators, such as catecholamine or fluoride. These differences suggest that the enzyme, once fully activated by Gpp(NH)p, may have undergone some modification that is not subject ot facile reversal.

Full Text

Duke Authors

Cited Authors

  • Lefkowitz, RJ; Caron, MG

Published Date

  • June 25, 1975

Published In

Volume / Issue

  • 250 / 12

Start / End Page

  • 4418 - 4422

PubMed ID

  • 166994

International Standard Serial Number (ISSN)

  • 0021-9258


  • eng

Conference Location

  • United States