Reaction catalyzed by N-acetyl-beta-glucosaminyl-glycoprotein 4-beta-N-acetylgalactosaminyltransferase (2.4.1.244)

		+			=			+
	UDP-N-acetyl-D-galactosamine	+		N-acetyl-beta-D-glucosaminyl-R group	=		UDP	+		N-acetyl-beta-D-galactosaminyl-(1,4)-N-acetyl-beta-D-glucosaminyl-R group