Hydrolysis of natural and synthetic substrates by α- l-fucosidase, β- d-glucuronidase and β- n-acetylhexosaminidase purified from molluscs

Abstract

1. 1. Several mollusc glycosidases have been studied for their activities towards natural substrates. α- l-Fucosidases from Chamelea gallina, Tapes rhomboideus and Mytilus edulis hydrolyze oligosaccharides (di, tri and pentasaccharides) with α1 → 2, α1 → 3 and α1 → 4 bonds, fucose-containing glycopeptides from bovine thyroglobulin and the porcine submandibular mucin (devoid of sialic acid); α- l-fucosidase from Littorina littorea hydrolyzes fucose-containing glycopeptides from bovine thyroglobulin. 2. 2. β- d-Glucuronidase from L. littorea hydrolyzes hyaluronic acid, chondroitin 4-sulfate and heparin with a very low activity; however, it is much more active on oligosaccharides (from the above-mentioned macromolecules) containing non-reducing terminal glucuronyl residues. 3. 3. β- N-Acetylhexosaminidase from Helicella ericetorum acts mainly with an endo-hydrolase activity on β1 → 4 N-acetylhexosamine linkages of ovalbumin, ovomucoid, chitin, hyaluronic acid and chondroitin 4. 4-sulfate; it has also a secondary exo-hydrolase activity on these substrates.