Reaction catalyzed by protein geranylgeranyltransferase type I (2.5.1.59)

		+		GST-CDC42	=			+		GST-S-geranylgeranyl-CDC42
	geranylgeranyl diphosphate	+		GST-CDC42	=		diphosphate	+		GST-S-geranylgeranyl-CDC42