TY  - JOUR
AU  - Gabriel, F.
AU  - Heidelberger, A.
AU  - Rentsch, D.
AU  - Giger, W.
AU  - Günther, K.
AU  - Kohler, H.-P.
TI  - A novel metabolic pathway for degradation of 4-nonylphenol environmental contaminants by Sphingomonas xenophaga Bayram
JO  - The journal of biological chemistry
VL  - 280
SN  - 0021-9258
CY  - Bethesda, Md.
PB  - Soc.
M1  - PreJuSER-47189
SP  - 15526 - 15533
PY  - 2005
N1  - Record converted from VDB: 12.11.2012
AB  - 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.
KW  - Carbon Isotopes
KW  - Carbon Radioisotopes
KW  - Environmental Pollutants: metabolism
KW  - Isomerism
KW  - Magnetic Resonance Spectroscopy
KW  - Mass Spectrometry
KW  - Phenols: metabolism
KW  - Sphingomonas: metabolism
KW  - Time Factors
KW  - Carbon Isotopes (NLM Chemicals)
KW  - Carbon Radioisotopes (NLM Chemicals)
KW  - Environmental Pollutants (NLM Chemicals)
KW  - Phenols (NLM Chemicals)
KW  - 4-nonylphenol (NLM Chemicals)
KW  - J (WoSType)
LB  - PUB:(DE-HGF)16
C6  - pmid:15665329
UR  - <Go to ISI:>//WOS:000228444800010
DO  - DOI:10.1074/jbc.M413446200
UR  - https://juser.fz-juelich.de/record/47189
ER  -