Copper amine oxidase from lentil seedlings was shown to be able to catalyze the oxidative deamination of the indoleamines tryptamine, 5-hydroxytryptamine, and 5-methoxytryptamine. These compounds showed saturation kinetics with Km values as normal substrates, but their oxidation led to irreversible loss of enzyme activity suggesting a covalent interaction with the enzyme, most probably through its cofactor 6-hydroxydopa (2,4,5-trihydroxyphenylalanine). These indoleamines acted as irreversible inhibitors of the enzyme only in the absence of oxygen but they brought about changes in the electronic spectra of the enzyme both in aerobiosis and in anaerobiosis. This study reports on the mechanism by which these compounds inhibit lentil amine oxidase which involves first the oxidation of indoleamines bound to 6-hydroxydopa followed by the formation of an irreversible covalent derivative. The same inhibitory mechanism could possibly lead to inactivation of mammalian amine oxidases involved in serotonin neurotransmitter metabolism in conditions of ischemia or hypoxia.

Medda, R., Padiglia, A., Finazzi Agrò, A., Pedersen, J., Lorrai, A., Floris, G. (1997). Tryptamine as substrate and inhibitor of lentil seedling copper amine oxidase. EUROPEAN JOURNAL OF BIOCHEMISTRY, 250(2), 377-382.

Tryptamine as substrate and inhibitor of lentil seedling copper amine oxidase

Finazzi Agrò A;Pedersen JZ;
1997-12-01

Abstract

Copper amine oxidase from lentil seedlings was shown to be able to catalyze the oxidative deamination of the indoleamines tryptamine, 5-hydroxytryptamine, and 5-methoxytryptamine. These compounds showed saturation kinetics with Km values as normal substrates, but their oxidation led to irreversible loss of enzyme activity suggesting a covalent interaction with the enzyme, most probably through its cofactor 6-hydroxydopa (2,4,5-trihydroxyphenylalanine). These indoleamines acted as irreversible inhibitors of the enzyme only in the absence of oxygen but they brought about changes in the electronic spectra of the enzyme both in aerobiosis and in anaerobiosis. This study reports on the mechanism by which these compounds inhibit lentil amine oxidase which involves first the oxidation of indoleamines bound to 6-hydroxydopa followed by the formation of an irreversible covalent derivative. The same inhibitory mechanism could possibly lead to inactivation of mammalian amine oxidases involved in serotonin neurotransmitter metabolism in conditions of ischemia or hypoxia.
1-dic-1997
Pubblicato
Rilevanza internazionale
Articolo
Esperti anonimi
Settore BIO/10 - BIOCHIMICA
English
Amine Oxidase (Copper-Containing); Fabaceae; Fluorescence; Oxidation-Reduction; Seeds; Tryptamines; Plants, Medicinal
Medda, R., Padiglia, A., Finazzi Agrò, A., Pedersen, J., Lorrai, A., Floris, G. (1997). Tryptamine as substrate and inhibitor of lentil seedling copper amine oxidase. EUROPEAN JOURNAL OF BIOCHEMISTRY, 250(2), 377-382.
Medda, R; Padiglia, A; Finazzi Agrò, A; Pedersen, J; Lorrai, A; Floris, G
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/210848
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