Glycosidases

Glycosidases are a family of enzymes that catalyze the hydrolysis of glycosidic bonds. They play an important role in the biodegradation of complex carbohydrates such as cellulose and starch and can be found in all domains of life. Among these, exo-glycosidases release a single monosaccharide from the nonreducing terminus of an oligosaccharide, and endo-glycosidases that cleave internal glycosidic bonds. Many glycosidases are widely used in the lab, including but not limited to agarase, amylase, beta-galactosidase, endo-H, lysozyme, neuraminidase and PNGase F. In molecular biology, agarase has been used in the efficient recovery of RNA or DNA for cloning, amplification, or sequencing. Amylase, which hydrolyzes starch, is used in starch tests, digestion studies, fermentation, and for selection in molecular biology. Beta-galactosidase is commonly used in molecular biology with X-gal, as a reporter marker when investigating gene expression. Endo H cleaves between two N-acetylglucosamine (GlcNAc) subunits and is used to study post-translational modifications. Lysozymes are commonly used to lyse Gram-positive bacteria, release proteins from organelles, study immune reactions, and free contents of bacterial periplasm. Neuraminidase, also known as sialidase, cleaves the terminal sialic acid residue from glycoproteins, while PNGase F is used for the study of proteins, especially for determining glycosylation.