Reaction catalyzed by (N-acetylneuraminyl)-galactosylglucosylceramide N-acetylgalactosaminyltransferase (2.4.1.92)

		+			=			+
	UDP-N-acetyl-D-galactosamine	+		GM3(N-acetylneuraminic acid)-ganglioside	=		UDP	+		GM2(N-acetylneuraminic acid)-ganglioside