Action of diverse peroxidases and laccases on six cell wall-related phenolic compounds

Abstract

Four peroxidases and four laccases were compared as to reaction rates catalysed with six phenolic substrates of relevance to the plant cell wall. When each phenolic substrate was tested at 670 μM and pH 6.0, in the presence of 670 μM H 2O 2 or ∼270 μM O 2 as the electron acceptor, all the peroxidases and laccases had similar substrate preferences: reaction rates were in the order sinapyl>coniferyl> p-coumaryl alcohols, and feruloyl> p-coumaroyl esters. Specific activities were in the order basic peroxidase>acidic peroxidase≫laccase. The data are consistent with the view that peroxidases rather than laccases play a major role in phenolic cross-linking in the cell wall.