This title appears in the Scientific Report :
2005
Please use the identifier:
http://dx.doi.org/10.1074/jbc.M413446200 in citations.
Please use the identifier: http://hdl.handle.net/2128/2668 in citations.
A novel metabolic pathway for degradation of 4-nonylphenol environmental contaminants by Sphingomonas xenophaga Bayram
A novel metabolic pathway for degradation of 4-nonylphenol environmental contaminants by Sphingomonas xenophaga Bayram
Several nonylphenol isomers with alpha-quaternary carbon atoms serve as growth substrates for Sphingomonas xenophaga Bayram, whereas isomers containing hydrogen atoms at the alpha-carbon do not. Three metabolites of 4-(1-methyloctyl)-phenol were isolated in mg quantities from cultures of strain Bayr...
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Personal Name(s): | Gabriel, F. |
---|---|
Heidelberger, A. / Rentsch, D. / Giger, W. / Günther, K. / Kohler, H.-P. | |
Contributing Institute: |
Phytosphäre; ICG-III |
Published in: | The @journal of biological chemistry, 280 (2005) S. 15526 - 15533 |
Imprint: |
Bethesda, Md.
Soc.
2005
|
Physical Description: |
15526 - 15533 |
DOI: |
10.1074/jbc.M413446200 |
PubMed ID: |
15665329 |
Document Type: |
Journal Article |
Research Program: |
Chemie und Dynamik der Geo-Biosphäre |
Series Title: |
Journal of Biological Chemistry
280 |
Subject (ZB): | |
Link: |
Get full text OpenAccess |
Publikationsportal JuSER |
Please use the identifier: http://hdl.handle.net/2128/2668 in citations.
Several nonylphenol isomers with alpha-quaternary carbon atoms serve as growth substrates for Sphingomonas xenophaga Bayram, whereas isomers containing hydrogen atoms at the alpha-carbon do not. Three metabolites of 4-(1-methyloctyl)-phenol were isolated in mg quantities from cultures of strain Bayram supplemented with the growth substrate isomer 4-(1-ethyl-1,4-dimethyl-pentyl)-phenol. They were unequivocally identified as 4-hydroxy-4-(1-methyl-octyl)-cyclohexa-2,5-dienone, 4-hydroxy-4-(1-methyl-octyl)-cyclohex-2-enone, and 2-(1-methyl-octyl)-benzene-1,4-diol by high pressure liquid chromatography-mass spectrometry and nuclear magnetic resonance spectroscopy. Furthermore, two metabolites originating from 4-n-nonylphenol were identified as 4-hydroxy-4-nonyl-cyclohexa-2,5-dienone and 4-hydroxy-4-nonyl-cyclohex-2-enone by high pressure liquid chromatography-mass spectrometry. We conclude that nonylphenols were initially hydroxylated at the ipso-position forming 4-alkyl-4-hydroxy-cyclohexa-2,5-dienones. Dienones originating from growth substrate nonylphenol isomers underwent a rearrangement that involved a 1,2-C,O shift of the alkyl moiety as a cation to the oxygen atom of the geminal hydroxy group yielding 4-alkoxyphenols, from which the alkyl moieties can be easily detached as alcohols by known mechanisms. Dienones originating from nongrowth substrates did not undergo such a rearrangement because the missing alkyl substituents at the alpha-carbon atom prevented stabilization of the putative alpha-carbocation. Instead they accumulated and subsequently underwent side reactions, such as 1,2-C,C shifts and dihydrogenations. The ipso-hydroxylation and the proposed 1,2-C,O shift constitute key steps in a novel pathway that enables bacteria to detach alpha-branched alkyl moieties of alkylphenols for utilization of the aromatic part as a carbon and energy source. |