Conversion of chlorobiphenyls into phenylhexasdienoates and benzoates by the enzymes of the upper pathway for polychlorobiphenyl degradation encoded by the bph locus of pseudomonas sp. strain LB400
- Gesellschaft fuer Biotechnologische Forschung-National Research Centre for Biotechnology, Braunschweig (Germany)
Metabolism of 21 chlorobiphenyls by the enzymes of the upper biphenyl catabolic pathway encoded by the bph locus of Pseudomonas sp. strain LB400 was investigated by using recombinant strains harboring gene cassettes containing bphABC or bphABCD. The enzymes of the upper pathway were generally able to metabolize mono- and dischlorinated biphenyls but only partially transform most trichlorinated congeners investigated: 14 of 15 mono- and dichlorinated and 2 of 6 trichlorinated congeners were converted into benzoates. All mono- and at leas 8 of 12 dichlorinated congeners were attacked by the bphA-encoded biphenyl dioxygenase virtually exclusively at ortho and meta carbons. This enzyme exhibited a high degree of selectivity for the aromatic ring to be attacked, with the order or ring preference being non- > ortho- > meta- > para-substituted for mono- and dichlorinated congeners. The influence of the chlorine substitution pattern of the metabolized ring on benzoate formation resembled its influence on the reactivity of initial dioxygenation, suggesting that the rate of benzoate formation may frequently be determined by the rate of initial attack. The absorption spectra of phenylhexadienoates formed correlated with the presence or absence of a chlorine substituent at an ortho position. 24 refs., 3 figs., 2 tabs.
- OSTI ID:
- 102595
- Journal Information:
- Applied and Environmental Microbiology, Vol. 61, Issue 7; Other Information: PBD: Jul 1995
- Country of Publication:
- United States
- Language:
- English
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