Inhibition of Peroxidase-Catalyzed Oxidation of Chromogenic Substrates by Propyl Gallate and Its Polydisulfide

Peroxidase-catalyzed oxidation of 2,2'-azino-di-(3-ethyl-2,3-dihydrobenzthiazoline-6-sulfonate) (ABTS) was competitively inhibited by propyl gallate (PG) and its polydisulfide (PGPDS) at 20° C in 0.015 M phosphate-citrate buffer (pH 6.0). Under these conditions, the values of the inhibition con...

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Bibliographic Details
Published in:Applied biochemistry and microbiology 2005-07, Vol.41 (4), p.330-335
Main Authors: Naumchik, I V, Karasyova, E I, Metelitza, DI
Format: Article
Language:English
Subjects:
Catalysis
Enzymes
Oxidation
Substrates
Vitaceae
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Summary:Peroxidase-catalyzed oxidation of 2,2'-azino-di-(3-ethyl-2,3-dihydrobenzthiazoline-6-sulfonate) (ABTS) was competitively inhibited by propyl gallate (PG) and its polydisulfide (PGPDS) at 20° C in 0.015 M phosphate-citrate buffer (pH 6.0). Under these conditions, the values of the inhibition constant (K^sub i^) were equal to 62 and 5.6 μM, respectively, for PG and PGPDS. The stoichiometric inhibition factor (f; the number of radicals extinguished per molecule of an inhibitor) equaled 2.0 and 14.7, respectively, for PG and PGPDS. Peroxidase-catalyzed oxidation of o-phenylenediamine was barely affected by PG or PGPDS. PGPDS may be used as a stop-reagent of peroxidase-catalyzed ABTS oxidation, whereas PG may serve as a calibrating inhibitor in test systems for measurement of total antioxidant activity (in human biological fluids, natural preparations, juices, wines, and other objects).[PUBLICATION ABSTRACT]
ISSN:0003-6838
1608-3024
DOI:10.1007/s10438-005-0056-y