Peroxidase-catalyzed desulfonation of 3,5-dimethyl-4-hydroxy and 3,5-dimethyl-4-aminobenzenesulfonic acids.
Horseradish peroxidase (HRP), lignin peroxidase (LiP), and Mn(III)-malonate (a manganese peroxidase mimic) oxidized 3,5-dimethyl-4-hydroxybenzenesulfonic acid (I) to 2,6-dimethyl-1,4-benzoquinone (III) and 2,6-dimethyl-1,3,4-trihydroxybenzene (IV). Only LiP was efficient at oxidizing 3,5-dimethyl-4-aminobenzenesulfonic acid (II); LiP oxidized II to 2,6-dimethyl-1,4-benzoquinone (III) and 2,6-dimethyl-3-hydroxy-1,4-benzoquinone (V). In these reactions, the H2O2-oxidized peroxidases or Mn(III)-malonate oxidized the aromatic ring by two electrons to produce a cation. Nucleophilic attack by water on the sulfonic acid bearing carbon eliminated sulfonic acid as inorganic sulfite and produced 2,6-dimethyl-1,4-benzoquinone (III). Possible mechanisms for the formation of IV and V are discussed.
Muralikrishna
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Department of Chemistry, Biochemistry, and Molecular Biology, Oregon Graduate Institute of Science & Technology, Portland 97291-1000.
Renganathan
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D001487:Basidiomycota / Q000201:enzymology; D001711:Biotransformation; D002851:Chromatography, High Pressure Liquid; D008401:Gas Chromatography-Mass Spectrometry; D006735:Horseradish Peroxidase / Q000378:metabolism; D007700:Kinetics; D008314:Malonates; D008345:Manganese; D015394:Molecular Structure; D010544:Peroxidases / Q000378:metabolism*; D013379:Substrate Specificity; D013425:Sulfanilic Acids / Q000378:metabolism*
D008314:Malonates; D013425:Sulfanilic Acids; D008345:Manganese; C030290:malonic acid; D006735:Horseradish Peroxidase; D010544:Peroxidases; C042858:lignin peroxidase; C051129:manganese peroxidase