Copper amine oxidase from lentil (Lens esculenta) seedlings was shown to catalyze the oxidative deamination of tyramine and three similar aromatic monoamines, benzylamine, phenylethylamine and 4-methoxyphenylethylamine. Tyramine, an important plant intermediate, was found to be both a substrate and an irreversible inhibitor of the enzyme whereas the other amines were not inhibitory. In the course of tyramine oxidation the enzyme gradually became inactivated with the concomitant appearance of a new absorption at 560 nm due to the formation of a stable adduct. Inactivation took place only in the presence of oxygen and was probably due to the reaction of the enzyme with the oxidation product of tyramine, phydroxyphenylacetaldehyde. The kinetic data obtained in this study indicate that tyramine represents a new interesting type of physiological mechanismbased inhibitor for plant copper amine oxidases.
Inhibition of lentil copper/TPQ amine oxidase by the mechanism-based inhibitor derived from tyramine / A., Padiglia; G., Floris; S., Longu; Schinina', Maria Eugenia; J. Z., Pedersen; A., Finazzi Agro'; F., De Angelis; R., Medda. - In: BIOLOGICAL CHEMISTRY. - ISSN 1431-6730. - STAMPA. - 385:3-4(2004), pp. 323-329. (Intervento presentato al convegno Conference on Oxygen and the Cell tenutosi a Berlin, GERMANY nel SEP, 2003) [10.1515/bc.2004.028].
Inhibition of lentil copper/TPQ amine oxidase by the mechanism-based inhibitor derived from tyramine
SCHININA', Maria Eugenia;
2004
Abstract
Copper amine oxidase from lentil (Lens esculenta) seedlings was shown to catalyze the oxidative deamination of tyramine and three similar aromatic monoamines, benzylamine, phenylethylamine and 4-methoxyphenylethylamine. Tyramine, an important plant intermediate, was found to be both a substrate and an irreversible inhibitor of the enzyme whereas the other amines were not inhibitory. In the course of tyramine oxidation the enzyme gradually became inactivated with the concomitant appearance of a new absorption at 560 nm due to the formation of a stable adduct. Inactivation took place only in the presence of oxygen and was probably due to the reaction of the enzyme with the oxidation product of tyramine, phydroxyphenylacetaldehyde. The kinetic data obtained in this study indicate that tyramine represents a new interesting type of physiological mechanismbased inhibitor for plant copper amine oxidases.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
