Figure 1.

Structure of 9-O-acetyl-GD2. O-acetylated GD2 is constituted by a ceramide chain, which is anchored into plasma membrane, and a hydrophile chain. Oligosaccharide chain and O-acetylation are oriented to extracellular matrix. O-acetyl-GD2 is formed by the addition of an O-acetyl ester to the external sialic acid residue by a 9(7)-O-acetyl transferase. O-Acetyl esters located at the C7 position are mobile and can spontaneously migrate to the C9 position. They can be removed by 9(7)-acetyl esterases. Cer, ceramide; Gal, galactose; GalNAc, N-acetylgalactosamine; Neu5Ac, N-acetylneuraminic acid.