Comparison of enzymatic and immunochemical properties of 2,3-dihydroxybiphenyl-1,2-dioxygenases from fourPseudomonasstrains

A 2,3-dihydroxybiphenyl-1,2-dioxygenase gene has been cloned from chromosomal DNA of Pseudomonas sp. DJ-12 which can grow on biphenyl or 4-chlorobiphenyl as the sole carbon and energy source. Enzymatic and immunochemical properties of the cloned 2,3-dihydroxybiphenyl-1,2-dioxygenase were characterized, and compared with those of P. pseudoalcaligenes KF707, Pseudomonas sp. KKS102, and P. putida OU83. The dioxygenase of Pseudomonas sp. DJ-12 was similar to those of P. pseudoalcaligenes KF707, and Pseudomonas sp. KKS102, but significantly different from that of P. putida OU83 in electrophoretic mobilities on native PAGE and SDS-PAGE. The dioxygenases of Pseudomonas sp. DJ-12 and P. putida OU83 exhibited the highest ring-fission activity to 3-methylcatechol, and those of P. pseudoalcaligenes KF707 and Pseudomonas sp. KKS102 to 2,3-dihydroxybiphenyl among 2,3-dihydroxybiphenyl, catechol, 3-methylcatechol, 4-methylcatechol, and 4-chlorocatechol as substrates. 2,3-dihydroxybiphenyl-1,2-dioxygenase of P. pseudoalcaligenes KF707 was immunochemically related to that of Pseudomonas sp. KKS102, but was different from those of Pseudomonas sp. DJ-12 and P. putida OU83.