Ac4ManNAz can be taken up by cells and is an azide-containing metabolic glycoprotein labeling reagent that selectively modifies proteins. Commonly used for cell labeling, tracking and proteomic analysis. Ac4ManNAz contains an Azide group and can undergo copper-catalyzed azide-alkyne cycloaddition reaction (CuAAc) with molecules containing Alkyne groups. Ac4ManNAz can also undergo strain-promoted alkyne-azide cycloaddition (SPAAC) with molecules containing DBCO or BCN groups.