What are N-acetylglucosaminidases?
N-Acetylglucosaminidases belong to the class of glycosidases, i.e. enzymes that cleave glycosides; a glycoside is a sugar with something attached. In the case of N-acetylglucosaminidase, the sugar is GlcNAc and the "something" is a chitin or chitosan oligomer. Thus, N-acetylglucosaminidase cleaves a single GlcNAc off the non-reducing end of a chitin/chitosan oligomer. N-Acetylglucosaminidases have the Enzyme Commission number EC 188.8.131.52, and they belong to a number of different Glycoside Hydrolase (GH) families according to the CAZY classification of Carbohydrate Active enZYmes, including GH3 and GH20. N-Acetylglucosaminidase (sometimes also called exo-N-acetylglucosaminidase, to distinguish them from the ill-named endo-N-acetylglucosaminidases cleaving N-glycan side chains off glycoproteins) should not be confused with exo-chitinase (which would cleave off dimers from the non-reducing or reducing end of a chitin or chitosan). N-Acetylglucosaminidases hydrolyze chitin oligomers, i.e. breakdown products of chitinase digestion of chitin polymers, into the monosaccharide GlcNAc. Also, they act in concert with glucosaminidases to hydrolyze chitosan oligomers, i.e. breakdown products of chitinase or chitosanase digestion of chitosan polymers, into the monosaccharides GlcNAc and GlcN. These two glycosidases can be used for the sequencing of purified partially acetylated chitosan oligomers.