N-azidoacetylglucosamine-tetraacylated (Ac4GlcNAz) is an azido-tagged analogue of N-acetylglucosamine (GlcNAC). It features azide functionality on the N-acyl side chain and is acetylated to aid in cell membrane permeation. Once in the cell, the acetylated compound is deprotected and takes part in the hexosamine biosynthetic pathway by action of GlcNAc kinase. The resulting modified proteins are detected by the addition of fluorescent tags under Cu(I)-catalyzed azide-alkyne cycloaddition conditions.
