What are glucosaminidases?

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Glucosaminidases belong to the class of glycosidases, i.e. enzymes that cleave glycosides; a glycoside is a sugar with something attached. In the case of glucosaminidase, the sugar is GlcN and the "something" is a chitosan oligomer. Thus, glucosaminidase cleaves a single GlcN off the non-reducing end of a chitosan oligomer. Glucosaminidases have the Enzyme Commission number EC 3.2.1.165, and they belong to a number of different Glycoside Hydrolase (GH) families according to the CAZY classification of Carbohydrate Active enZYmes, including GH2, GH9, and GH35, but few have been characterized. Glucosaminidase (sometimes also called exo-glucosaminidase, though the "exo" is not really required as there are no endo-glucosaminidases) should not be confused with exo-chitosanase (which would cleave off dimers from the non-reducing or reducing end of a chitosan - but natural exo-chitosanases have not yet been identified). Glucosaminidases act in concert with N-acetylglucosaminidases to hydrolyze chitosan oligomers, i.e. breakdown products of chitinase or chitosanase digestion of chitosan polymers, into the monosaccharides GlcN and GlcNAc. These two glycosidases can be used for the sequencing of purified partially acetylated chitosan oligomers.