Characterization of 2,6-dichloro-p-hydroquinone 1,2-dioxygenase (PcpA) of Sphingomonas chlorophenolica ATCC 39723

Biochem Biophys Res Commun. 1999 Dec 20;266(2):322-5. doi: 10.1006/bbrc.1999.1805.


Pentachlorophenol (PCP) is a general biocide and a major environmental pollutant. The initial steps of PCP degradation by Sphingomonas chlorophenolica ATCC 39723 have been studied and characterized. Two enzymes are responsible for converting PCP to 2, 6-dichloro-p-hydroquinone (2,6-DiCH) which is a common metabolic intermediate of the biodegradation of polychlorinated phenols. 2, 6-DiCH is degraded by PcpA from strain ATCC 39723, but the reaction end product has been misidentified as 6-chlorohydroxyquinol and has been elusive to detection. We report here the overproduction of PcpA in Escherichia coli and the demonstration of quantitative conversion of 2,6-DiCH to 2-chloromaleylacetate with the coconsumption of one equivalent O(2) and release of one equivalent Cl(-) by purified PcpA. On the basis of the reaction stoichiometry, the enzyme is proposed to be 2,6-DiCH 1,2-dioxygenase.

Publication types

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

MeSH terms

  • Bacterial Proteins / chemistry
  • Dioxygenases*
  • Escherichia coli / genetics
  • Escherichia coli / metabolism
  • Hydrogen-Ion Concentration
  • Hydroquinones / metabolism
  • Kinetics
  • Maleates / analysis
  • Maleates / metabolism
  • Mass Spectrometry
  • Oxygenases / biosynthesis
  • Oxygenases / chemistry*
  • Oxygenases / genetics
  • Phencyclidine / metabolism
  • Recombinant Proteins / chemistry
  • Spectrophotometry, Ultraviolet
  • Sphingomonas / enzymology*
  • Sphingomonas / genetics


  • Bacterial Proteins
  • Hydroquinones
  • Maleates
  • Recombinant Proteins
  • 2,6-dichloro-4-hydroquinone
  • 2-chloromaleylacetate
  • 2,6-dichlorohydroquinone dioxygenase
  • Oxygenases
  • Dioxygenases
  • Phencyclidine

Associated data

  • GENBANK/M55159