A novel sialidase capable of cleaving 3-deoxy-D-glycero-D-galacto-2-nonulosonic acid (KDN).
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.
Li
Y T
YT
Department of Biochemistry, Tulane University School of Medicine, New Orelans, Louisiana 70112.
Yuziuk
J A
JA
Li
S C
SC
Nematalla
A
A
Hasegawa
A
A
Kimura
M
M
Nakagawa
H
H
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*
D005679:G(M3) Ganglioside; D006027:Glycosides; D012794:Sialic Acids; D013400:Sugar Acids; C050008:3-deoxyglycero-galacto-nonulosonic acid; D009439:Neuraminidase; D019158:N-Acetylneuraminic Acid