The mechanism of guanosine nucleotide hydrolysis by p21 c-Ha-ras. The stereochemical course of the GTPase reaction |
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| Authors: | J Feuerstein R S Goody M R Webb |
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| Institution: | Max-Planck Institut für Medizinische Forschung, Abteilung Biophysik, Heidelberg, West Germany. |
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| Abstract: | The use of guanosine 5'-O-(gamma-thio)triphosphate as a substrate for p21 c-Ha-ras was established. By using chirally labeled gamma-17O,18O]guanosine 5'-O-(gamma-thio)triphosphate, the stereochemical course of the GTPase reaction was determined. The analysis shows that the hydrolysis occurs with inversion at the gamma-phosphorus. This shows that the most likely mechanism is a single step, in-line transfer, without a phosphoenzyme or other phosphorylated intermediate. |
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