Peptitergent PD1 affects the GTPase activity of rat brain cortical membranes. |
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| Authors: | A Bavec A Juréus B Cigi? U Langel M Zorko |
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| Affiliation: | Institute of Biochemistry, Medical Faculty, University of Ljubljana, Slovenia. |
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| Abstract: | Peptitergent PD1 shows complex effects on GTPase activity of rat brain cortical membranes: inhibition in the presence of lower concentrations of GTP and activation at a higher concentration, above 0.5 microM, of GTP. Its effect is dose dependent and is characterized by an EC50 of 1.8 +/- 0.2 microM and a Hill coefficient of 1.6 +/- 0.3, and it increases both Km and Vmax of the GTP hydrolysis. PD1 that was unable to solubilize G-proteins from the membranes probably acts on them by direct binding near the C-terminal alpha-helical region of the Galpha subunit, similarly to mastoparan. |
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