TY - JOUR
T1 - Prostaglandin-stimulated GTP hydrolysis associated with activation of adenylate cyclase in human platelet membranes
AU - Lester, H. A.
AU - Steer, M. L.
AU - Levitzki, A.
PY - 1982
Y1 - 1982
N2 - In membranes purified from human blood platelets, basal guanosine triphosphate (GTP) hydrolysis is reduced by a factor of ≃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 K(m) 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.
AB - In membranes purified from human blood platelets, basal guanosine triphosphate (GTP) hydrolysis is reduced by a factor of ≃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 K(m) 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.
UR - https://www.scopus.com/pages/publications/0020026548
U2 - 10.1073/pnas.79.3.719
DO - 10.1073/pnas.79.3.719
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C2 - 6121325
AN - SCOPUS:0020026548
SN - 0027-8424
VL - 79
SP - 719
EP - 723
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 3 I
ER -
