Endoglycosidase

An Endoglycosidase is an enzyme that releases oligosaccharides from glycoproteins or glycolipids. Or it merely cleaves polysacharride chains between residues that are not the terminal residue, although releasing oligosaccharides from conjugated protein and lipid molecules is more common.

It breaks the glycosidic bonds between two sugar monomer in the polymer. It is different from exoglycosidase that it does not do so at the terminal residue. Hence, it is used to release long carbohydrates from conjugated molecules. If an exoglycosidase were used, every monomer in the polymer would have to be removed, one by one from the chain, taking a long time. An endoglycosidase cleaves, giving a polymeric product.

PROTEIN-x1-x2-x3-x4-x5-x6-x7-x8-x9-x10-x11-...-xn

A exoglycosidase would remove each carohydrate monomer (x) one by one from the end, starting at xn, whereas and endogylcosidae can cut at any glycosidic bond (-) and may cleave after a signature 'link oligosaccharide' that links certain carbohydrates to certain proteins.

For more information on linkages to proteins see O- and N- linked glycoproteins