InterPro domain: IPR004888

O-Glycosyl hydrolases ( 3.2.1. ) are a widespread group of enzymes that hydrolyse the glycosidic bond between two or more carbohydrates, or between a carbohydrate and a non-carbohydrate moiety. A classification system for glycosyl hydrolases, based on sequence similarity, has led to the definition of 85 different families [ 1 , 2 ]. This classification is available on the CAZy (CArbohydrate-Active EnZymes) website.

This family of enzymes belongs to glycosyl hydrolase family 63 ( GH63 ). They catalyse the specific cleavage of the non-reducing terminal glucose residue from Glc(3)Man(9)GlcNAc(2). Mannosyl oligosaccharide glucosidase 3.2.1.106 is the first enzyme in the N-linked oligosaccharide processing pathway.

This family also includes glucosylglycerate hydrolase which catalyses the hydrolysis of glucosylglycerate to glycerate and glucose, during the mycobacterial recovery from nitrogen starvation. This process promotes the rapid mobilisation of the glucosylglycerate that accumulates under these conditions. This enzyme can also hydrolyse mannosylglycerate with lower efficiency [ 3 ].

1. Conserved catalytic machinery and the prediction of a common fold for several families of glycosyl hydrolases. Proc. Natl. Acad. Sci. U.S.A. 92, 7090-4
2. Structures and mechanisms of glycosyl hydrolases. Structure 3, 853-9
3. The structural characterization of a glucosylglycerate hydrolase provides insights into the molecular mechanism of mycobacterial recovery from nitrogen starvation. IUCrJ 6, 572-585