Reaction catalyzed by xylosylprotein 4-beta-galactosyltransferase (2.4.1.133)

		+			=			+
	UDP-alpha-D-galactose	+		2-naphthyl beta-D-xylopyranoside	=		UDP	+		4-beta-D-galactosyl-2-naphthyl-beta-D-xylopyranoside