sentences:  The enzyme O-GlcNAcase is involved in removal of N-acetylglucosamine groups from serine and threonine residues in the cytoplasm and nucleus of the cell.The glycoside hydrolases are involved in the biosynthesis and degradation of glycogen in the body.Glycoside hydrolases are classified into EC 3.2.1 as enzymes catalyzing the hydrolysis of O- or S-glycosides.