Sabater F, Sánchez-Bravo J, Acosta M. Effects of enzyme/substrate ratio and of cofactors on the oxidation products of indole-3-acetic acid catalyzed by peroxidase.
REVISTA ESPANOLA DE FISIOLOGIA 1983;
39:169-173. [PMID:
6622807]
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Abstract
During the oxidation of indole-3-acetic acid catalyzed by peroxidase, the relative amounts of the products closely depends on the enzyme/substrate ratio. In the absence of cofactors, high enzyme/substrate ratio induces a rise in the level of indole-3-aldehyde and indole-3-methanol, and a drop in that of oxindoles. 2,4-dichlorophenol, although a very efficient cofactor, promotes inhibition of the oxidation after a few minutes, presumably through the formation of a phenol-derivative inhibitor. 2-4-dichlorophenol also inhibits the production of oxindoles at all stages. Both inhibitory effects are abolished by a low concentration of enzyme. Mn2+, itself a weak inhibitor, synergizes the catalytic effect of 2,4-dichlorophenol, perhaps by preventing the formation of the inhibitor. The results are discussed against more widely accepted mechanisms of indole-3-acetic acid oxidation.
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