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Prostaglandin-Stimulated GTP Hydrolysis Associated with Activation of Adenylate Cyclase in Human Platelet Membranes

Lester, Henry A. and Steer, Michael L. and Levitzki, Alexander (1982) Prostaglandin-Stimulated GTP Hydrolysis Associated with Activation of Adenylate Cyclase in Human Platelet Membranes. Proceedings of the National Academy of Sciences of the United States of America, 79 (3). pp. 719-723. ISSN 0027-8424. PMCID PMC345823.

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In membranes purified from human blood platelets, basal guanosine triphosphate (GTP) hydrolysis is reduced by a factor of approx 6 by exposure to N-ethylmaleimide (10 mM). This decreased background enables the detection of an additional GTP hydrolysis in the presence of prostaglandin E1 (PGE1). The PGE1-stimulated GTPase has several properties correlated with PGE1-stimulated adenylate cyclase in this preparation. The two enzymes have similar dose-response relationships (half-maximal stimulation at 0.1 µM PGE1). Exposure to cholera toxin blocks the PGE1-stimulated GTPase and activates adenylate cyclase. Both enzymes are activated by submicromolar concentrations of GTP, although the Km for the GTPase is about 10 times greater than that for the adenylate cyclase. The data are discussed in relation to the hypothesis that hormone-stimulated adenylate cyclase (i) is activated as a regulatory component binds a molecule of GTP and (ii) is deactivated as this molecule is hydrolyzed.

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URLURL TypeDescription CentralArticle
Lester, Henry A.0000-0002-5470-5255
Additional Information:© 1982 by the National Academy of Sciences Communicated by John J. Hopfield, September 14, 1981 We thank H. Arad, D. Atlas, S. Braun, D. Cassel, M. Lowe, and M. Schramm for advice and discussion. This research was supported by the U.S.-Israel Binational Science Foundation and by the National Institutes of Health (Grants GM-26604 and GM-29836 and Research Career Development Award NS-272 to H.A.L., and Research Career Development Award NS-160 to M.L.S.). The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U. S. C. §1734 solely to indicate this fact.
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Binational Science Foundation (USA-Israel)UNSPECIFIED
Subject Keywords:cholera toxin; N-ethylmaleimide; epinephrine
Issue or Number:3
PubMed Central ID:PMC345823
Record Number:CaltechAUTHORS:LESpnas82
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:6584
Deposited By: Archive Administrator
Deposited On:13 Dec 2006
Last Modified:02 Oct 2019 23:34

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