GTP (gammaS) and GDP (betaS) as electron donors: new wine in old bottles

Life Sci. 1999;65(11):1135-40. doi: 10.1016/s0024-3205(99)00347-1.


G proteins are membrane-bound regulatory proteins which modulate the activity of ion channels and other effector systems. The GTP and GDP analogs GTP (gammaS) and GDP (betaS) have been used to study the role of G proteins in numerous physiologic systems. The prolonged effects of these analogs have been thought to be due to the fact that they are nonhydrolyzable. However, in this paper we show that the GTP (gammaS) and GDP (betaS) analogs are potent reducing agents at physiologic pH. This observation suggests that previous data obtained using these compounds may need to be reinterpreted.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cytochrome c Group / metabolism
  • Dithionitrobenzoic Acid / metabolism
  • Dose-Response Relationship, Drug
  • Guanosine 5'-O-(3-Thiotriphosphate) / pharmacology*
  • Guanosine Diphosphate / analogs & derivatives*
  • Guanosine Diphosphate / pharmacology
  • Oxidation-Reduction
  • Thionucleotides / pharmacology*


  • Cytochrome c Group
  • Thionucleotides
  • Guanosine Diphosphate
  • Guanosine 5'-O-(3-Thiotriphosphate)
  • guanosine 5'-O-(2-thiodiphosphate)
  • Dithionitrobenzoic Acid