THE CHLOROPEROXIDASE-CATALYZED OXIDATION OF PHENOLS - MECHANISM, SELECTIVITY, AND CHARACTERIZATION OF ENZYME-SUBSTRATE COMPLEXES
Articolo
Data di Pubblicazione:
1994
Citazione:
THE CHLOROPEROXIDASE-CATALYZED OXIDATION OF PHENOLS - MECHANISM,
SELECTIVITY, AND CHARACTERIZATION OF ENZYME-SUBSTRATE COMPLEXES / L. CASELLA, S. POLI, M. GULLOTTI, C. SELVAGGINI, T. BERINGHELLI, A. MARCHESINI. - In: BIOCHEMISTRY. - ISSN 0006-2960. - 33:21(1994), pp. 6377-6386. [10.1021/bi00187a001]
Abstract:
The reactivity of a series of para-substituted phenolic compounds in the
peroxidation catalyzed by chloroperoxidase was investigated, and the
results were interpreted on the basis of the binding characteristics of
the substrates to the active site of the enzyme. Marked selectivity
effects are observed. These operate through charge, preventing phenolic
compounds carrying amino groups on the substituent chain to act as
substrates for the enzyme, and through size, excluding potential
substrates containing bulky substituents to the phenol nucleus. Also,
chiral recognition is exhibited by chloroperoxidase in the oxidation of
N-acetyltyrosine, where only the L isomer is oxidized. Kinetic
measurements show that, in general, the efficiency of chloroperoxidase
in the oxidation of phenols is lower than that of horseradish
peroxidase. Paramagnetic NMR spectra and relaxation rate measurements of
chloroperoxidase-phenol complexes are consistent with binding of the
substrates close to the heme, in the distal pocket, with the phenol
group pointing toward the iron atom. On the other hand, phenolic
compounds which are not substrates for chloroperoxidase bind to the
enzyme with a much different disposition, with the phenol group very
distant from the iron and probably actually outside the active-site
cavity.
Tipologia IRIS:
01 - Articolo su periodico
Elenco autori:
L. Casella, S. Poli, M. Gullotti, C. Selvaggini, T. Beringhelli, A. Marchesini
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