Molecular function

GM2 synthase activity, GM2/GD2-synthase activity, GalNAc-T activity, UDP acetylgalactosamine-(N-acetylneuraminyl)-D-galactosyl-D-glucosylceramide acetylgalactosaminyltransferase activity, UDP-N-acetyl-D-galactosamine:(N-acetylneuraminyl)-D-galactosyl-D-glucosylceramide N-acetyl-D-galactosaminyltransferase activity, UDP-N-acetyl-D-galactosamine:1-O-[O-(N-acetyl-alpha-neuraminosyl)-(2->3)-O-beta-D-galactopyranosyl-(1->4)-beta-D-glucopyranosyl]-ceramide 1,4-beta-N-acetyl-D-galactosaminyltransferase activity, UDP-N-acetylgalactosamine GM3 N-acetylgalactosaminyltransferase activity, asialo-GM2 synthase activity, beta-1,4N-aetylgalactosaminyltransferase activity, ganglioside GM2 synthase activity, ganglioside GM3 acetylgalactosaminyltransferase activity, uridine diphosphoacetylgalactosamine-acetylneuraminylgalactosylglucosylceramide acetylgalactosaminyltransferase activity, uridine diphosphoacetylgalactosamine-ganglioside GM3 acetylgalactosaminyltransferase activity, uridine diphosphoacetylgalactosamine-hematoside acetylgalactosaminyltransferase activity

Catalysis of the reaction: UDP-N-acetyl-D-galactosamine + (N-acetylneuraminyl)-D-galactosyl-D-glucosylceramide = UDP + N-acetyl-D-galactosaminyl-(N-acetylneuraminyl)-D-galactosyl-D-glucosylceramide.