Enzymatic degradation of 2,6-dichlorophenol by horseradish peroxidase: UV-visible and mass spectrometry characterization of the reaction products [corrected]

J Inorg Biochem. 2002 Sep 30;92(1):75-81. doi: 10.1016/s0162-0134(02)00488-9.

Abstract

The reaction mechanism of the oxidation of 2,6-dichlorophenol (2,6-DCP) by horseradish peroxidase (HRP) and H2O2 has been investigated and the reaction products have been characterized by UV-visible and mass spectrometry. Evidence for the dimerization of 2,6-DCP to 3,3',5,5'-tetrachloro-4,4'-dihydroxybiphenyl and the subsequent fast oxidation of this product to the corresponding 3,3',5,5'-tetrachlorodiphenoquinone have been collected. The reaction rate was found to decrease markedly as soon as the pH was raised, with a clear inflection point at pH congruent with 6.6-6.9; it also resulted independent from H2O2 concentration. Since the pK(a) for 2,6-DCP is 6.80, the reaction rate might be influenced by the protonation state of the substrate.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Benzoquinones / metabolism
  • Catalysis
  • Chlorophenols / metabolism*
  • Horseradish Peroxidase / metabolism*
  • Hydrogen Peroxide / pharmacology
  • Hydrogen-Ion Concentration
  • Kinetics
  • Mass Spectrometry
  • Protons
  • Spectrophotometry, Ultraviolet

Substances

  • Benzoquinones
  • Chlorophenols
  • Protons
  • 3,3'5,5'-tetrachlorodiphenoquinone
  • Hydrogen Peroxide
  • Horseradish Peroxidase
  • 2,6-dichlorophenol