The mechanism of guanosine nucleotide hydrolysis by p21 c-Ha-ras. The stereochemical course of the GTPase reaction

J Biol Chem. 1989 Apr 15;264(11):6188-90.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphate / metabolism
  • GTP Phosphohydrolases / metabolism*
  • Guanosine 5'-O-(3-Thiotriphosphate)
  • Guanosine Triphosphate / analogs & derivatives
  • Guanosine Triphosphate / metabolism*
  • Hydrolysis
  • Magnetic Resonance Spectroscopy
  • Phosphoric Monoester Hydrolases / metabolism*
  • Proto-Oncogene Proteins / metabolism*
  • Proto-Oncogene Proteins p21(ras)
  • Recombinant Proteins / metabolism
  • Stereoisomerism
  • Thionucleotides / metabolism


  • Proto-Oncogene Proteins
  • Recombinant Proteins
  • Thionucleotides
  • Guanosine 5'-O-(3-Thiotriphosphate)
  • Guanosine Triphosphate
  • Adenosine Triphosphate
  • Phosphoric Monoester Hydrolases
  • GTP Phosphohydrolases
  • Proto-Oncogene Proteins p21(ras)