Notice of RetractionCloning, Expression, and Characterization of Recombinant Hydroxyquinol-1, 2-Dioxygenase from Pseudomonas sp. strain HS-D38

Hydroxyquinol 1, 2-Dioxygenase is a key enzyme for p-nitrophenol (PNP) catabolism in bacterium. In this paper, we cloned a pnpC gene encoding hydroxyquinol-1, 2-dioxygenase from Pseudomonas sp. strain HS-D38 that could degrade PNP efficiently. The open reading frame of the pnpC contained 873 nucleotides and the deduced molecular mass of gene product (PnpC) was 33 kDa The recombinant enzyme was highly expressed in E. coli BL21(DE3) as a histidine-tag fusion protein and purified to homogeneity by Ni-NAT affinity chromatography. The specific activity of the purified protein reached at 9.3 U/mg. The maximum activity of the recombinant enzyme towards catechol was exhibited at 45 V and pH5.0. The enzyme activity could be stimulated by 0.2 mM of Fe3+, Fe2+, Cu2+, Zn2+, Mn2+, and Co2+. The above results provided useful information for PnpC application in biodegradation of PNP pollutants.