Zhao J S, Singh A, Huang X D, Ward O P
Department of Biology, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1.
Appl Environ Microbiol. 2000 Jun;66(6):2336-42. doi: 10.1128/AEM.66.6.2336-2342.2000.
Biotransformation products of hydroxylaminobenzene and aminophenol produced by 3-nitrophenol-grown cells of Pseudomonas putida 2NP8, a strain grown on 2- and 3-nitrophenol, were characterized. Ammonia, 2-aminophenol, 4-aminophenol, 4-benzoquinone, N-acetyl-4-aminophenol, N-acetyl-2-aminophenol, 2-aminophenoxazine-3-one, 4-hydroquinone, and catechol were produced from hydroxylaminobenzene. Ammonia, N-acetyl-2-aminophenol, and 2-aminophenoxazine-3-one were produced from 2-aminophenol. All of these metabolites were also found in the nitrobenzene transformation medium, and this demonstrated that they were metabolites of nitrobenzene transformation via hydroxylaminobenzene. Production of 2-aminophenoxazine-3-one indicated that oxidation of 2-aminophenol via imine occurred. Rapid release of ammonia from 2-aminophenol transformation indicated that hydrolysis of the imine intermediate was the dominant reaction. The low level of 2-aminophenoxazine-3-one indicated that formation of this compound was probably due to a spontaneous reaction accompanying oxidation of 2-aminophenol via imine. 4-Hydroquinone and catechol were reduction products of 2- and 4-benzoquinones. Based on these transformation products, we propose a new ammonia release pathway via oxidation of aminophenol to benzoquinone monoimine and subsequent hydrolysis for transformation of nitroaromatic compounds by 3-nitrophenol-grown cells of P. putida 2NP8. We propose a parallel mechanism for 3-nitrophenol degradation in P. putida 2NP8, in which all of the possible intermediates are postulated.
对恶臭假单胞菌2NP8(一种能在2-硝基苯酚和3-硝基苯酚上生长的菌株)在3-硝基苯酚培养基中生长时产生的羟基氨基苯和氨基酚的生物转化产物进行了表征。羟基氨基苯产生了氨、2-氨基酚、4-氨基酚、4-苯醌、N-乙酰基-4-氨基酚、N-乙酰基-2-氨基酚、2-氨基吩恶嗪-3-酮、4-对苯二酚和儿茶酚。2-氨基酚产生了氨、N-乙酰基-2-氨基酚和2-氨基吩恶嗪-3-酮。所有这些代谢产物也在硝基苯转化培养基中被发现,这表明它们是通过羟基氨基苯进行硝基苯转化的代谢产物。2-氨基吩恶嗪-3-酮的产生表明2-氨基酚通过亚胺发生了氧化。2-氨基酚转化过程中氨的快速释放表明亚胺中间体的水解是主要反应。2-氨基吩恶嗪-3-酮的低水平表明该化合物的形成可能是由于2-氨基酚通过亚胺氧化时伴随的自发反应。4-对苯二酚和儿茶酚是2-苯醌和4-苯醌的还原产物。基于这些转化产物,我们提出了一种新的氨释放途径,即通过氨基酚氧化为苯醌单亚胺并随后水解,由恶臭假单胞菌2NP8在3-硝基苯酚培养基中生长的细胞对硝基芳香化合物进行转化。我们提出了恶臭假单胞菌2NP中3-硝基苯酚降解的平行机制,其中假设了所有可能的中间体。