Purification and degradation characteristics of Biphenyl degrading enzyme BphC from Aquamicrobium sp. SK-2

Abstract

 In the present study, we purified the biphenyl-degrading enzyme 2, 3-dihydroxybiphenyl-1, 2-dioxygenase (BphC) from the bacteria Aquamicrobium sp. SK-2. The BphC was dimer and had molecular weight of 65 kDa. This enzyme showed activity at wide range of temperatures, and from a neutral to an alkali pH, it showed highest activity, at 30°C and pH 8, respectively. The BphC showed K_m (12.0 μM) and V_max(154 mM/min) values with the substrate 2, 3-dihydroxybiphenyl. This result indicated that the BphC had a relatively high affinity with the substrate 2, 3-dihydroxybiphenyl. We analyzed the N-terminal amino acid sequence of the purified enzyme. Sequencing results denoted that the enzyme BphC from SK-2 had high homology (92%) with the enzyme of Pseudomonas sp. KKS102. Based on these results we concluded that BphC was involved in the ring-opening reactions of 2, 3-dihydroxybiphenyl and catechol.