title: A novel sialidase capable of cleaving 3-deoxy-D-glycero-D-galacto-2-nonulosonic acid (KDN).
abstract: We have examined the tissues of several species of fish and found that the liver of the loach (Misgurnus fossilis) contains a novel sialidase capable of efficiently hydrolyzing 3-deoxy-D-glycero-D-galacto-2-nonulosonic acid (KDN) from the 4-methylumbelliferyl alpha-ketoside of KDN, KDN alpha 2-->3Gal beta 1-->4GlcCer and KDN alpha 2-->6 N-acetylgalactosaminitol as well as Neu5Ac from the 4-methylumbelliferyl alpha-ketoside of Neu5Ac and GM3. The pH optimum for this enzyme was determined to be 4.6, and the Km using the 4-methylumbelliferyl alpha-ketoside of KDN and 4-methylumbelliferyl alpha-ketoside of Neu5Ac as substrates were 0.07 and 0.12 mM, respectively. The enzyme was stable in the pH range of 4 to 5 but very unstable above pH 6. This is the first report of a sialidase capable of efficiently cleaving glycosidically linked KDN.
authors.affiliation: Department of Biochemistry, Tulane University School of Medicine, New Orelans, Louisiana 70112.
authors.forename: Y T
authors.initials: YT
authors.lastname: Li
authors.forename: J A
authors.initials: JA
authors.lastname: Yuziuk
authors.forename: S C
authors.initials: SC
authors.lastname: Li
authors.forename: A
authors.initials: A
authors.lastname: Nematalla
authors.forename: A
authors.initials: A
authors.lastname: Hasegawa
authors.forename: M
authors.initials: M
authors.lastname: Kimura
authors.forename: H
authors.initials: H
authors.lastname: Nakagawa
mesh_terms: D000818:Animals; D002240:Carbohydrate Sequence; D003013:Clostridium / Q000201:enzymology; D003531:Cypriniformes; D005679:G(M3) Ganglioside / Q000031:analogs & derivatives; D006027:Glycosides / Q000378:metabolism*; D008099:Liver / Q000201:enzymology*; D008969:Molecular Sequence Data; D019158:N-Acetylneuraminic Acid; D009439:Neuraminidase / Q000378:metabolism*; D012794:Sialic Acids / Q000737:chemistry; D013379:Substrate Specificity; D013400:Sugar Acids / Q000378:metabolism*
chemical_list: D005679:G(M3) Ganglioside; D006027:Glycosides; D012794:Sialic Acids; D013400:Sugar Acids; C050008:3-deoxyglycero-galacto-nonulosonic acid; D009439:Neuraminidase; D019158:N-Acetylneuraminic Acid