title: Purification and characterization of N-acetyl-alpha-D-galactosaminidase from Gallus domesticus.
abstract: Exoglycosidases modify carbohydrate epitopes on glycoproteins and glycolipids. The N-acetyl-alpha-D-galactosaminidase from the domestic chicken, Gallus domesticus, is an important exoglycosidase which degrades the human blood group A epitope. This enzyme has never been demonstrably purified or thoroughly characterized. We have developed a technique to purify this enzyme to homogeneity. The isolated enzyme has a molecular weight of 49.1 kDa by SDS PAGE and 145.0 kDa by gel filtration. The enzyme is highly selective for PNP-N-acetyl-alpha-D-galactosaminide and is inactive against other low molecular weight substrates. The enzyme hydrolyzes the terminal N-acetyl-alpha-D-galactosaminide residues from blood group A2 erythrocytes. Protease activity is below detectable limits. The enzyme has a pH optima of 3.7, a pI of 8.15, is relatively unaffected by ionic strength, and is stable at 4 degrees C.
authors.affiliation: Department of Pathology, University of Missouri, Columbia.
authors.forename: J
authors.initials: J
authors.lastname: Hata
authors.forename: M
authors.initials: M
authors.lastname: Dhar
authors.forename: M
authors.initials: M
authors.lastname: Mitra
authors.forename: M
authors.initials: M
authors.lastname: Harmata
authors.forename: F
authors.initials: F
authors.lastname: Haibach
authors.forename: P
authors.initials: P
authors.lastname: Sun
authors.forename: D
authors.initials: D
authors.lastname: Smith
mesh_terms: D000017:ABO Blood-Group System; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002645:Chickens; D002846:Chromatography, Affinity; D004591:Electrophoresis, Polyacrylamide Gel; D004795:Enzyme Stability; D006596:Hexosaminidases / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008099:Liver / Q000201:enzymology; D008970:Molecular Weight; D013379:Substrate Specificity; D048809:alpha-N-Acetylgalactosaminidase
chemical_list: D000017:ABO Blood-Group System; D000596:Amino Acids; D006596:Hexosaminidases; C482722:NAGA protein, human; D048809:alpha-N-Acetylgalactosaminidase