preferred_name: alpha-D-mannosyl-(1->3)-N-acetyl-alpha-D-galctosaminyl-1-diphospho-di-trans,octa-cis-undecaprenol + GDP + H(+) => N-acetyl-alpha-D-galactosaminyl-di-trans,octa-cis-undecaprenyl diphosphate + GDP-alpha-D-mannose