TAILIEUCHUNG - Báo cáo Y học: A novel meta-cleavage dioxygenase that cleaves a carboxyl-groupsubstituted 2-aminophenol Purification and characterization of 4-amino-3-hydroxybenzoate 2,3-dioxygenase from Bordetella sp. strain 10d

A bacterial strain that grew on 4-amino-3-hydroxybenzoic acidwas isolated fromfarmsoil. The isolate, strain 10d, was identified as a species of . strain10dgrownon4-amino-3-hydroxybenzoicacid containedanenzyme that cleaved this enzyme was purified to homogeneity with a 110-fold increase in specific activity. The purified enzyme was characterized as a meta-cleavage dioxygenase that catalyzed the ring fission betweenC2 andC3 of 4-amino-3-hydroxybenzoic acid, with the consumption of 1 mol of O2per mol of substrate | Eur. J. Biochem. 269 5871-5877 2002 FEBS 2002 doi A novel meta-cleavage dioxygenase that cleaves a carboxyl-group-substituted 2-aminophenol Purification and characterization of 4-amino-3-hydroxybenzoate 2 3-dioxygenase from Bordetella sp. strain 10d Shinji Takenaka1 Tokiko Asami2 Chika Orii2 Shuichiro Murakami1 and Kenji Aoki1 1 Department of Biofunctional Chemistry Faculty of Agriculture and 2Division of Science of Biological Resources Graduate School of Science and Technology Kobe University Japan A bacterial strain that grew on 4-amino-3-hydroxybenzoic acid was isolated from farm soil. The isolate strain 10d was identified as a species of Bordetella. Cell extracts of Borde-tella sp. strain 10d grown on 4-amino-3-hydroxybenzoic acid contained an enzyme that cleaved this substrate. The enzyme was purified to homogeneity with a 110-fold increase in specific activity. The purified enzyme was characterized as a meta-cleavage dioxygenase that catalyzed the ring fission between C2 and C3 of 4-amino-3-hydroxybenzoic acid with the consumption of 1 mol of O2 per mol of substrate. The enzyme was therefore designated as 4-amino-3-hydroxy-benzoate 2 3-dioxygenase. The molecular mass of the native enzyme was 40 kDa based on gel filtration the enzyme is composed of two identical 21-kDa subunits according to SDS PAGE. The enzyme showed a high dioxygenase activity only for 4-amino-3-hydroxybenzoic acid. The Km and Vmax values for this substrate were 35 M and 12 pmol-min-1- mg protein -1 respectively. Of the 2-amino-phenols tested only 4-aminoresorcinol and 6-amino-m-cresol inhibited the enzyme. The enzyme reported here differs from previously reported extradiol dioxygenases including 2-aminophenol 1 6-dioxygenase in molecular mass subunit structure and catalytic properties. Keywords 4-amino-3-hydroxybenzoate-degrading bacterium 2-aminophenol derivatives meta-cleavage dioxygenase 4-amino-3-hydroxybenzoate 2 3-dioxygenase. Dioxygenases catalyzing .

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