Reaction catalyzed by protein geranylgeranyltransferase type I (2.5.1.59)

		+		Rho-cysteine	=		S-geranylgeranyl-Rho	+
	geranylgeranyl diphosphate	+		Rho-cysteine	=		S-geranylgeranyl-Rho	+		diphosphate