Enzymatic degradation of 2,6-dichlorophenol by horseradish peroxidase: UV-visible and mass spectrometry characterization of the reaction products [corrected].
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.
Laurenti
Enzo
E
Dipartimento di Chimica I.F.M., Università di Torino, Turin, Italy.
Ghibaudi
Elena
E
Todaro
Gianpiero
G
Pia Ferrari
Rosa
R
D016227:Benzoquinones / Q000378:metabolism; D002384:Catalysis; D002733:Chlorophenols / Q000378:metabolism*; D006735:Horseradish Peroxidase / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D013058:Mass Spectrometry; D011522:Protons; D013056:Spectrophotometry, Ultraviolet
D016227:Benzoquinones; D002733:Chlorophenols; D011522:Protons; C048435:3,3'5,5'-tetrachlorodiphenoquinone; D006861:Hydrogen Peroxide; D006735:Horseradish Peroxidase; C032729:2,6-dichlorophenol