• Korean Journal of Microbiology
• /
• v.40 no.3
• /
• pp.199-204
• /
• 2004

The parathion hydrolase (OPH) produced by Pseudomonas rhodesiae H5 was purified by ammonium sulfate precipitation, DEAE-Toyopearl 650M ion exchange chromatography and Sephadex gel filtration chromatography. Parathion hydrolase from crude extracts of P. rhodesiae H5 has two components designated as OPH $I_1$ and OPH $I_2$, Optimum pH and temperature of OPH $I_1$and OPH $I_2$ were pH 7.2 and $30^{\circ}C$, and pH 7.6 and $37^{\circ}C$, respectively. The activation energy of OPH $I_1$ for the hydrolysis of parathion was 3.01 ㎉/I, II, III in the temperature range of $4^{\circ}C$ to $30^{\circ}C$, and Michaelis constant ($K_m$) for parathion was 69.2 ${\mu}M$. The activation energy of OPH $I_2$ for the hydrolysis of parathion was 4.07㎉/㏖ in the temperature range of $4^{\circ}C$ to $37^{\circ}C$, and Michaelis constant for parathion was 150.9${\mu}M$. Furthermore OPH $I_1$ was completely inhibited by 1 mM $Ca^2+$, $Cu^2+$, $Mg^2+$, $Ni^2+$, but OPH $I_2$ was less inhibited than OPH $I_1$ by the metals used in this study.

• Journal of Microbiology and Biotechnology
• /
• v.17 no.11
• /
• pp.1890-1893
• /
• 2007

A bacterium, Burkholderia sp. JBA3, which can mineralize the pesticide parathion, was isolated from an agricultural soil. The strain JBA3 hydrolyzed parathion to p-nitrophenol, which was further utilized as the carbon and energy sources. The parathion hydrolase was encoded by a gene on a plasmid that strain JBA3 harbored, and it was cloned into pUC19 as a 3.7-kbp Sau3AI fragment. The ORF2 (ophB) in the cloned fragment encoded the parathion hydrolase composed of 526 amino acids, which was expressed in E. coli DH10B. The ophB gene showed no significant sequence similarity to most of other reported parathion hydrolase genes.