L-Azidoacetylgalactosamine-Tetraacylated

N-azidoacetylgalactosamine-tetraacylated (Ac4GalNAz) provides the first part of a simple and robust two-step technique that helps identify and characterise cell surface sialic acid-containing glycoproteins. The azide-modified protein is detected with either fluorescent alkynes or biotin alkyne. The acetyl groups increase cell permeability and allow the unnatural sugars to easily pass through the cell membrane. Carboxyesterases remove the acetyl groups once the monosaccharide is in the cell.