preferred_name: a beta-D-3-sulfogalactosyl-(1->4)-beta-D-glucosyl-(1<->1')-ceramide + N-acetyl-beta-D-galactosamine => N-acetyl-beta-D-galactosaminyl-(1->4)-beta-D-3-sulfogalactosyl-(1->4)-beta-D-glucosyl-(1<->1')-ceramide + H2O