Toluene and ethylbenzene oxidation by purified naphthalene dioxygenase from Pseudomonas sp. strain NCIB 9816-4

Appl Environ Microbiol. 1996 Sep;62(9):3101-6. doi: 10.1128/AEM.62.9.3101-3106.1996.

Abstract

Purified naphthalene dioxygenase (NDO) from Pseudomonas sp. strain NCIB 9816-4 oxidized toluene to benzyl alcohol and benzaldehyde by reactions involving benzylic monooxygenation and dioxygen-dependent alcohol oxidation, respectively. Xylene and nitrotoluene isomers were also oxidized to substituted benzyl alcohol and benzaldehyde derivatives. NDO oxidized ethylbenzene sequentially through (S)-1-phenethyl alcohol (77% enantiomeric excess) and acetophenone to 2-hydroxyacetophenone. In addition, NDO also oxidized ethylbenzene through styrene to (R)-1-phenyl-1,2-ethanediol (74% enantiomeric excess) by reactions involving desaturation and dihydroxylation, respectively. Isotope experiments with 18O2, H2 18O, and D2O suggest that 1-phenethyl alcohol is oxidized to acetophenone by a minor reaction involving desaturation followed by tautomerization. The major reaction in the conversion of 1-phenethyl alcohol and benzyl alcohol to acetophenone and benzaldehyde, respectively, probably involves monohydroxylation to form a gem-diol intermediate which stereospecifically loses the incoming hydroxyl group to leave the carbonyl product. These results are compared with similar reactions catalyzed by cytochrome P-450.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Benzene Derivatives / metabolism*
  • Dioxygenases
  • Multienzyme Complexes / pharmacology*
  • Oxidation-Reduction
  • Oxygenases / pharmacology*
  • Pseudomonas / enzymology*
  • Toluene / metabolism*

Substances

  • Benzene Derivatives
  • Multienzyme Complexes
  • Toluene
  • Oxygenases
  • Dioxygenases
  • naphthalene dioxygenase
  • ethylbenzene