Reaction catalyzed by glucuronylgalactosylproteoglycan 4-beta-N-acetylgalactosaminyltransferase (2.4.1.174)

		+			=			+
	UDP-N-acetyl-D-galactosamine	+		GlcUAbeta1-3Galbeta1-3Galbeta1-4Xyl(2-O-phosphate)	=		UDP	+		N-acetyl-D-galactosaminyl-1-4beta-D-GlcUAbeta1-3Galbeta1-3Galbeta1-4Xyl(2-O-phosphate)