title: Metabolism of 2,2'-dihydroxybiphenyl by Pseudomonas sp. strain HBP1: production and consumption of 2,2',3-trihydroxybiphenyl.
abstract: Cells of Pseudomonas sp. strain HBP1 grown on 2-hydroxy- or 2,2'-dihydroxybiphenyl contain NADH-dependent monooxygenase activity that hydroxylates 2,2'-dihydroxybiphenyl. The product of this reaction was identified as 2,2',3-trihydroxybiphenyl by 1H nuclear magnetic resonance and mass spectrometry. Furthermore, the monooxygenase activity also hydroxylates 2,2',3-trihydroxybiphenyl at the C-3' position, yielding 2,2',3,3'-tetrahydroxybiphenyl as a product. An estradiol ring cleavage dioxygenase activity that acts on both 2,2',3-tri- and 2,2',3,3'-tetrahydroxybiphenyl was partially purified. Both substrates yielded yellow meta-cleavage compounds that were identified as 2-hydroxy-6-(2-hydroxyphenyl)-6-oxo-2,4-hexadienoic acid and 2-hydroxy-6-(2,3-dihydroxyphenyl)-6-oxo-2,4-hexadienoic acid, respectively, by gas chromatography-mass spectrometry analysis of their respective trimethylsilyl derivatives. The meta-cleavage products were not stable in aqueous incubation mixtures but gave rise to their cyclization products, 3-(chroman-4-on-2-yl)pyruvate and 3-(8-hydroxychroman-4-on-2-yl)pyruvate, respectively. In contrast to the meta-cleavage compounds, which were turned over to salicylic acid and 2,3-dihydroxybenzoic acid, the cyclization products are not substrates to the meta-cleavage product hydrolase activity. NADH-dependent salicylate monooxygenase activity catalyzed the conversions of salicylic acid and 2,3-dihydroxybenzoic acid to catechol and pyrogallol, respectively. The partially purified estradiol ring cleavage dioxygenase activity that acted on the hydroxybiphenyls also produced 2-hydroxymuconic semialdehyde and 2-hydroxymuconic acid from catechol and pyrogallol, respectively.
authors.affiliation: Swiss Federal Institute for Water Resources and Water Pollution Control (EAWAG), Dübendorf.
authors.forename: H P
authors.initials: HP
authors.lastname: Kohler
authors.forename: A
authors.initials: A
authors.lastname: Schmid
authors.forename: M
authors.initials: M
authors.lastname: van der Maarel
mesh_terms: D001713:Biphenyl Compounds / Q000378:metabolism*; D002396:Catechols / Q000378:metabolism; D005231:Fatty Acids, Unsaturated / Q000378:metabolism; D062385:Hydroxybenzoates / Q000378:metabolism; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D006899:Mixed Function Oxygenases / Q000378:metabolism; D015394:Molecular Structure; D010636:Phenols / Q000378:metabolism*; D011549:Pseudomonas / Q000201:enzymology / Q000378:metabolism*; D011748:Pyrogallol / Q000378:metabolism; D012459:Salicylates / Q000378:metabolism; D013056:Spectrophotometry, Ultraviolet; D013379:Substrate Specificity
chemical_list: D001713:Biphenyl Compounds; D002396:Catechols; D005231:Fatty Acids, Unsaturated; D062385:Hydroxybenzoates; D010636:Phenols; D012459:Salicylates; D011748:Pyrogallol; C002091:hydroxymuconic semialdehyde; C009135:2,3-dihydroxybenzoic acid; C067814:3-(2-hydroxyphenyl)catechol; D006899:Mixed Function Oxygenases; C022619:salicylate 1-monooxygenase; C034221:catechol; C038764:2,2'-biphenol