title: Purification and properties of a galacturonic acid-releasing exopolygalacturonase from a strain of Bacillus.
abstract: An exopolygalacturonase [exo-PGase; poly (1,4-alpha-D-galacturonide) galacturonohydrolase, EC 3.2.1.67] was found to be extracellularly produced by Bacillus sp. strain KSM-P443. The exo-PGase was purified to homogeneity, as judged by polyacrylamide gel electrophoresis, through sequential column chromatographies. The enzyme had a molecular weight of approximately 45,000 and an isoelectric point of pH 5.8. The N-terminal sequence was Ser-Met-Gln-Lys-Ile-Lys-Asp-Glu-Ile-Leu-Lys-Thr-Leu-Lys-Val-Pro-Val-Phe and had no sequence similarity to those of other pectinolytic enzymes reported to date. Maximum activity toward polygalacturonic acid (PGA) was observed at 60 degrees C and at pH 7.0 in 100 mM Tris-HCl buffer without requiring any metal ions. When the chain length of oligogalacturonic acids increased, the apparent Km for them decreased, but the kcat values increased. This is the first bacterial exo-PGase that releases exclusively mono-galacturonic acid from PGA, di-, tri-, tetra-, and penta-galacturonic acids.
authors.affiliation: Tochigi Research Laboratories of Kao Corporation, Haga, Japan. 113310@kastanet.kao.co.jp
authors.forename: T
authors.initials: T
authors.lastname: Kobayashi
authors.forename: N
authors.initials: N
authors.lastname: Higaki
authors.forename: N
authors.initials: N
authors.lastname: Yajima
authors.forename: A
authors.initials: A
authors.lastname: Suzumatsu
authors.forename: H
authors.initials: H
authors.lastname: Hagihara
authors.forename: S
authors.initials: S
authors.lastname: Kawai
authors.forename: S
authors.initials: S
authors.lastname: Ito
mesh_terms: D001407:Bacillus / Q000201:enzymology*; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004591:Electrophoresis, Polyacrylamide Gel; D006603:Hexuronic Acids / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents; D007700:Kinetics; D011096:Polygalacturonase / Q000302:isolation & purification* / Q000494:pharmacology*; D013501:Surface-Active Agents; D013696:Temperature; D014783:Viscosity
chemical_list: D006603:Hexuronic Acids; D007202:Indicators and Reagents; D013501:Surface-Active Agents; C007819:galacturonic acid; D011096:Polygalacturonase