> as lemmas

1954 H. Schmitz et al. in Jrnl. Biol. Chem. 209 46 Isolation of guanosine-5′-phosphates (GMP, GDP, and GTP).

1992 Sci. Amer. July 39/1 (in figure) After a few seconds, the alpha subunit converts GTP to GDP, thereby inactivating itself. The alpha subunit will then reassociate with the beta-gamma complex.

2010 J. L. Tymoczko et al. Biochemistry xii. 178 The bound GTP acts as a built-in clock.