CMP-N-acetyl-9-O-acetyl-beta-neuraminate + a ganglioside GM1 (d18:1(4E)) => a ganglioside Ac-O-9-GD1a (d18:1(4E)) + CMP + H(+)
cmp-n-acetyl-9-o-acetyl-beta-neuraminate + a ganglioside gm1 (d18:1(4e)) => a ganglioside ac-o-9-gd1a (d18:1(4e)) + cmp + h(+)