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Oxidation of hydroxycinnamic acid and hydroxycinnamyl alcohol derivatives by laccase and peroxidase. Interactions among p ‐hydroxyphenyl, guaiacyl and syringyl groups during the oxidation reactions
Author(s) -
Takahama Umeo
Publication year - 1995
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1034/j.1399-3054.1995.930110.x
Subject(s) - laccase , peroxidase , chemistry , alcohol oxidation , alcohol , hydroxycinnamic acid , organic chemistry , enzyme , antioxidant
Fungal laccase oxidized derivatives of hydroxycinnamic acid. The rates decreased in the order sinapic acid > ferulic acid ≥ p ‐coumaric acid. The laccase oxidized sinapyl alcohol faster than coniferyl alcohol. The rates of oxidation of the hydroxycinnamic acid derivatives by an isoenzyme of peroxidase from horseradish decreased in the order p ‐coumaric acid > ferulic acid ≥ sinapic acid. The peroxidase oxidized coniferyl alcohol much faster than sinapyl alcohol. The laccase and the peroxidase predominantly oxidized (a) ferulic acid in a reaction mixture that contained p ‐coumaric acid and ferulic acid, (b) sinapic acid in a mixture of p ‐coumaric acid plus sinapic acid, and (c) sinapic acid in a mixture of ferulic acid plus sinapic acid. In a reaction mixture that contained both coniferyl and sinapyl alcohols, both fungal laccase and horseradish peroxidase predominantly oxidized sinapyl alcohol. From these results, it is concluded (1) that the p ‐hydroxyphenyl radical can oxidize guaiacyl and syringyl groups and produce their radicals and (2) that the guaiacyl radical can oxidize the syringyl group under formation of its radical; and that (3) in both cases the reverse reactions are very slow.