Reaction catalyzed by caffeate O-methyltransferase (2.1.1.68)

		+			=			+
	S-adenosyl-L-methionine	+		3-(3,4-dihydroxyphenyl)propanoic acid	=		S-adenosyl-L-homocysteine	+		3-(4-hydroxy-3-methoxyphenyl)propanoic acid