Reaction catalyzed by glucosylceramide beta-1,4-galactosyltransferase (2.4.1.274)

		+			=			+
	UDP-alpha-D-galactose	+		beta-D-glucosyl-(1<->1)-ceramide	=		UDP	+		beta-D-galactosyl-(1->4)-beta-D-glucosyl-(1<->1)-ceramide