Reaction catalyzed by chitobiosyldiphosphodolichol beta-mannosyltransferase (2.4.1.142)

		+			=			+
	GDP-alpha-D-mannose	+		N-acetyl-beta-D-glucosaminyl-(1->4)-N-acetyl-alpha-D-glucosaminyl-diphosphodolichol	=		GDP	+		beta-D-mannosyl-(1->4)-N-acetyl-beta-D-glucosaminyl-(1->4)-N-acetyl-alpha-D-glucosaminyl-diphosphodolichol