Reaction catalyzed by glucuronosyl-galactosyl-proteoglycan 4-alpha-N-acetylglucosaminyltransferase (2.4.1.223)

		+			=			+
	UDP-N-acetyl-D-glucosamine	+		beta-D-glucuronosyl-(1-3)-beta-D-galactosyl-1-O-naphthalenemethanol	=		UDP	+		alpha-N-acetyl-D-glucosaminyl-(1-4)-beta-D-glucuronosyl-(1-3)-beta-D-galactosyl1-O-naphthalenemethanol