Hammett rho sigma correlation for the inhibition by indoles of coniferyl alcohol oxidation catalyzed by cell wall peroxidases.
The inhibitory effect of indole-3-acetic acid, and of its peroxidase-mediated degradation products of an indole nature, on the oxidation rate of coniferyl alcohol catalyzed by cell wall peroxidases has been studied. The results show that the inhibitory effect of indole-3-acetic acid and indole-3-carbinol may be explained, in part, by their properties as peroxidase substrates. However, I50 values for a series of indole compounds not regarded as peroxidase substrates show a good correlation with the electron-donating or electron-withdrawing nature of the 3-substituents, as judged by the linearity of the Hammett rho sigma plot. These results suggest that although the properties of indole compounds as peroxidase substrates may be responsible, in part, for their inhibitory effects on the peroxidase-mediated oxidation of coniferyl alcohol, the inhibitory effect appears to be mainly determined by the acidity of the imino group of the indole nucleus.
Ferrer
M A
MA
Department of Plant Biology (Plant Physiology), University of Murcia, Spain.
Pedreño
M A
MA
Muñoz
R
R
Ros Barceló
A
A
D002384:Catalysis; D002473:Cell Wall / Q000201:enzymology*; D004583:Electrons; D007211:Indoles / Q000494:pharmacology*; D010084:Oxidation-Reduction; D010544:Peroxidases / Q000378:metabolism*; D010636:Phenols / Q000378:metabolism*; D010944:Plants / Q000201:enzymology
D007211:Indoles; D010636:Phenols; C010559:coniferyl alcohol; D010544:Peroxidases