Purification and characterization of a beta-glucuronidase from Aspergillus niger.
A beta-glucuronidase from Pectinex Ultra SP-L, a commercial pectolytic enzyme preparation from Aspergillus niger, was purified 170-fold by ion-exchange chromatography and gel filtration. Apparent M(r) of the purified enzyme, estimated by denaturing gel electrophoresis and size-exclusion chromatography, were 68,000 and 71,000, respectively, indicating that the enzyme is a monomeric protein. It released uronic acids not only from p-nitrophenyl beta-glucosiduronic acid (PNP-GlcA) but also from acidic galactooligosaccharides carrying either beta-D-glucosyluronic or 4-O-methyl-beta-D-glucosyluronic residues at the nonreducing termini through beta-(1-->6)-glycosidic linkages. The enzyme exhibited a maximal activity toward these substrates at pH 3.0. A regioisomer, 3-O-beta-glucosyluronic acid-galactose, was unsusceptible to the enzyme. The enzyme did act on a polymer substrate, releasing uronic acid from the carbohydrate portion of a radish arabinogalactan-protein modified by treatment with fungal alpha-L-arabinofuranosidase. The enzyme produced acidic oligosaccharides by transglycosylation, catalyzing the transfer of uronic acid residues of PNP-GlcA and 6-O-beta-glucosyluronic acid-galactose to certain exogenous acceptor sugars such as Gal, N-acetylgalactosamine, Glc, and xylose.
Kuroyama
H
H
Department of Biochemistry and Molecular Biology, Faculty of Science, Saitama University, 255 Shimo-okubo, Urawa 338-8570, Japan.
Tsutsui
N
N
Hashimoto
Y
Y
Tsumuraya
Y
Y
D001234:Aspergillus niger / Q000201:enzymology*; D002236:Carbohydrate Conformation; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D005966:Glucuronidase / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009844:Oligosaccharides / Q000737:chemistry / Q000378:metabolism; D013379:Substrate Specificity; D014574:Uronic Acids / Q000378:metabolism
D009844:Oligosaccharides; D014574:Uronic Acids; D005966:Glucuronidase