title: Purification and characterization of a Coffea canephora alpha-D-galactosidase isozyme.
abstract: Exoglycosidases modify carbohydrate epitopes on glycoproteins and glycolipids. The alpha-D-galactosidase from Coffea canephora is an important exoglycosidase which degrades the human blood group B epitope. Although multiple isozymes have been described, they have never been demonstrably purified and thoroughly characterized. We have developed a technique to purify an isozyme to homogeneity. The isolated enzyme has a molecular weight of 36.7 kDa by SDS PAGE and 34.0 kDa by gel filtration. The isozyme is highly selective for alpha-D-galactosides and inactive against other low molecular weight substrates. It hydrolyzes the the terminal alpha-D-galactosyl residue from the blood group B epitope. Protease activity is below detectable limits. The isozyme has a broad pH optima at 6.3, a pl of 7.03, is unaffected by ionic strength, and is stable at 4 degrees C.
authors.affiliation: Department of Pathology, University of Missouri, Columbia.
authors.forename: F
authors.initials: F
authors.lastname: Haibach
authors.forename: J
authors.initials: J
authors.lastname: Hata
authors.forename: M
authors.initials: M
authors.lastname: Mitra
authors.forename: M
authors.initials: M
authors.lastname: Dhar
authors.forename: M
authors.initials: M
authors.lastname: Harmata
authors.forename: P
authors.initials: P
authors.lastname: Sun
authors.forename: D
authors.initials: D
authors.lastname: Smith
mesh_terms: D000596:Amino Acids / Q000032:analysis; D002846:Chromatography, Affinity; D002850:Chromatography, Gel / Q000379:methods; D003069:Coffee / Q000201:enzymology*; D004591:Electrophoresis, Polyacrylamide Gel; D006863:Hydrogen-Ion Concentration; D007527:Isoenzymes / Q000302:isolation & purification* / Q000378:metabolism; D007700:Kinetics; D008970:Molecular Weight; D009994:Osmolar Concentration; D013379:Substrate Specificity; D000519:alpha-Galactosidase / Q000302:isolation & purification* / Q000378:metabolism
chemical_list: D000596:Amino Acids; D003069:Coffee; D007527:Isoenzymes; D000519:alpha-Galactosidase