Intrinsic nucleotide exchange on RAS

Inactive RAS:GDP is converted at a low rate to the active GTP-bound state through release of GDP and binding of GTP. This intrinsic GEF activity is weak due to the picomolar affinity of the protein for both nucleotides, but is stimulated by the interaction of RAS proteins with guanine nucleotide exchange factors (Marshall et al, 2012; reviewed in Bourne et al, 1991; Hennig et al, 2015; Pei et al, 2018).

非活性RAS：GDP在释放GDP并结合GTP的过程中以低比率转化为活性GTP结合态。这种内在的GEF活性因蛋白质对两种核苷酸的皮摩尔亲和力而较弱，但可通过RAS蛋白与鸟苷酸交换因子（Marshall等，2012；参见Bourne等，1991；Hennig等，2015；Pei等，2018）的相互作用而得到增强。