Artigo Produção Nacional Revisado por pares

Horseradish peroxidase-catalyzed aerobic oxidation of indole-3-acetic acid

1992; Elsevier BV; Volume: 296; Issue: 1 Linguagem: Inglês

10.1016/0003-9861(92)90541-4

ISSN

1096-0384

Autores

Mariza Pires de Melo, Jorge A. Escobar, Diana Metodiewa, H. Brian Dunford, Giuseppe Cilento,

Tópico(s)

Pharmaceutical and Antibiotic Environmental Impacts

Resumo

Light emission from the horseradish peroxidase-catalyzed aerobic or anaerobic oxidation of indole-3-acetic acid has been investigated under opposite extreme conditions of enzyme/substrate ratio. The O2-dependent chemiluminescent processes represent a minor part of the total oxygen consumption. Superoxide is involved in chemiexcitation as is evident from the observed inhibitory effect of superoxide dismutase. At high enzyme/substrate ratio, only a part of the emission is dependent on superoxide ion; at low ratio the dependence is extensive. At high ratio, some of the emission is independent of superoxide and O2. The identical quenching effects of d-and l-tryptophan are consistent with the formation of the quenching species only in bulk solution. The similarity of the emission spectra under extreme conditions indicates that the same main emitters are formed. This is also supported by the effect of quenchers. Possibly some of the emitters originate in the oxidative cleavage of the 2,3-double bond of the indole ring.

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