title: Effect of divalent metal ions and glycerol on the GTPase activity of H-ras proteins.
abstract: The product of the protooncogenic ras gene (p21N ras) exhibits a weak GTPase activity. A significant increase in the GTPase activity associated with p21N ras protein was obtained by using glycerol in the assay mixture. Of the several metal ions tested, only Mg++ and Mn++ are effective divalent cations that support the GTPase activity of p21N ras protein. p21N ras protein exhibits higher GTPase activity and yields higher [3H] GDP binding in the presence of MnCl2 than with MgCl2. Optimal GTPase and [3H] GDP binding are obtained at micromolar concentrations of MgCl2 or MnCl2. Concentrations in the millimolar range of either MgCl2 or MnCl2 are inhibitory to the GTPase activity, whereas [3H] GDP binding was not affected.
authors.forename: V
authors.initials: V
authors.lastname: Manne
authors.forename: H F
authors.initials: HF
authors.lastname: Kung
mesh_terms: D002413:Cations, Divalent; D020558:GTP Phosphohydrolases / Q000378:metabolism*; D005990:Glycerol / Q000494:pharmacology; D006153:Guanosine Diphosphate / Q000378:metabolism; D008274:Magnesium / Q000494:pharmacology; D008345:Manganese / Q000494:pharmacology; D009857:Oncogenes; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism*; D011506:Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D002413:Cations, Divalent; D011506:Proteins; D006153:Guanosine Diphosphate; D008345:Manganese; D010744:Phosphoric Monoester Hydrolases; D020558:GTP Phosphohydrolases; D008274:Magnesium; D005990:Glycerol