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Chemical and functional analysis of components of adenylyl cyclase from human platelets treated with phorbolesters
Author(s) -
Simmoteit Robert,
Schulzki Horst-Dieter,
Palm Dieter,
Mollner Stefan,
Pfeuffer Thomas
Publication year - 1991
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(91)80734-k
Subject(s) - adenylyl cyclase , platelet , chemistry , adcy9 , adcy10 , biochemistry , microbiology and biotechnology , pharmacology , medicine , enzyme , biology
Human platelets, prelabeled with [ 32 P]phospate were treated with tetradecanoylphorbol acetate (TPA) for 5 min at 37°C. Phosphorylation of the components of adenylyl cyclase was determined in membranes using specific antibodies against G‐proteins and the catalytic moiety. Less than 0.01 mol of [ 32 P]phosphate/mol could be detected in immunoprecipitates using antibodies against sequences within the α‐subunit of the GTP binding protein G i . TPA, however, caused the incorporation of 0.67–1.1 mol of [ 32 P]phosphate per mol of catalyst while 0.13‐0.2 mol were found in the absence or TPA. Lack of modification of the α‐subunit of G i was also indicated by the results of reconstitution experiments with purified G iα from bovine brain: adenylyl cyclase in membranes from untreated platelets was significantly more inhibited by added G iα , than that from TPA treated cells. While β,γ‐subunits were like‐wise inhibitory no difference dependent on platelet‐pretreatment could be observed.