Catechol 1,2-dioxygenase from α-naphthol degrading thermophilic Geobacillus sp. strain: Purification and properties

Abstract

The purpose of this study was purification and characterization of catechol 1,2-dioxygenase from Geobacillus sp. G27 strain, which degrades α-naphthol by the β-ketoadipate pathway. The catechol 1,2-dioxygenase (C1,2O) was purified using four steps of ammonium sulfate precipitation, DEAE-celullose, Sephadex G-150 and hydroxylapatite chromatographies. The enzyme was purified about 18-fold with a specific activity of 7.42 U mg of protein -1 . The relative molecular mass of the native enzyme estimated on gel chromatography of Sephadex G-150 was 96 kDa. The pH and temperature optima for enzyme activity were 7 and 60°C, respectively. A half-life of the catechol 1,2-dioxygenase at the optimum temperature was 40 min. The kinetic parameters of the Geobacillus sp. G27 strain catechol 1,2-dioxygenase were determined. The enzyme had apparent K m of 29 μM for catechol and the cleavage activities for methylcatechols were much less than for catechol and no activity with gentisate or protocatechuate was detected. © 2009 Versita Warsaw and Springer-Verlag Berlin Heidelberg.