Reaction catalyzed by GDP-Man:Man3GlcNAc2-PP-dolichol alpha-1,2-mannosyltransferase (2.4.1.131)

		+		oligosaccharide-lipid acceptor	=			+		alpha-mannosyl-1,2-oligosaccharide-lipid
	GDP-mannose	+		oligosaccharide-lipid acceptor	=		GDP	+		alpha-mannosyl-1,2-oligosaccharide-lipid