[摘要]：2,3-Dihydroxybiphenyl-1,2-dioxygenase plays an important role in the degradation of polychlorinated biphenyls. The gene (BsbphCI) encoding a 2,3-DHBP dioxygenase from Bacillus sp. JF8 is 960 bp. We synthesized a 960 bp BsbphCI gene encoding a 2,3-DHBP dioxygenase derived from Bacillus sp. JF8 and expressed it in Escherichia coli. The recombinant protein was about 36 kDa, confirmed by SDS-PAGE. The concentration of the purified protein was about 1.8 mg/mL. With 2,3-DHBP as a substrate, the optimal temperature for enzyme activity at pH 8.5 was 50 degrees C. The optimal pH for the 2,3-DHBP dioxygenase was 8.5. The enzyme retained 33% activity after heating at 60 degrees C for 60 min. We found that Cu2+, K+, Zn2+, Mg2+, Ni2+, CO2+, and Cd2+ activated the enzyme. However, Ca2+, Fe2+, Li+, and Cr3+ inhibited it. Enzyme activity was reduced by exposure to H2O2, SDS, and KI. The results of HPLC indicated that the transgenic E. coli strain with the BstvhCI gene degraded 2,3-DHBP more quickly than the wild type strain. (C) 2012 Elsevier Inc. All rights reserved.
