||Li G, Qian H. Kinetic timing: a novel mechanism that improves the accuracy of GTPase timers in endosome fusion and other biological processes. Traffic. 2002 Apr3(4):249-55. link p.252 caption to figure 3 PubMed ID11929606
||Abstract:"Here, [investigators] describe a mathematical model that shows how a directional GTPase cycle, in a nonequilibrium steady-state driven by GTP hydrolysis, can significantly reduce the variance in the lifetime of an activated GTPase molecule and thereby increase the accuracy and efficiency of the timer."
||p.252 caption to figure 3:"With these parameters, the equilibrium constant for GTP hydrolysis Keq=10^8, and the free energy ΔG½=-11 kcal/mol, corresponding to approximately the energy for a phosphate bond at 2mM