Reaction catalyzed by protein-S-isoprenylcysteine O-methyltransferase (2.1.1.100)

		+		(RhoAA) C-terminal S-farnesyl-L-cysteine	=			+
	S-adenosyl-L-methionine	+		(RhoAA) C-terminal S-farnesyl-L-cysteine	=		S-adenosyl-L-homocysteine	+		(RhoA) C-terminal S-farnesyl-L-cysteine methyl ester