Lycorine: A powerful inhibitor of L-galactono-γ-lactone dehydrogenase activity

• Published in: Journal of plant physiology Vol. 150; no. 3; pp. 362 - 364
• Main Authors: Arrigoni, Oreste, De Gara, Laura, Paciolla, Costantino, Evidente, Antonio, de Pinto, Maria C., Liso, Rosalia
• Format: Journal Article
• Language: English
• Published: Jena Elsevier GmbH 1997; Elsevier
• Subjects: ACIDE ASCORBIQUE; ACIDO ASCORBICO; ALCALOIDE; ALCALOIDES; ALKALOIDS; ALLIUM CEPA; ascorbate biosynthesis; ASCORBIC ACID; ASCORBINSAEUREBIOSYNTHESE; ASCORBINSAEUREMETABOLISMUS; AVENA SATIVA; Biological and medical sciences; BIOSINTESIS; BIOSYNTHESE; BIOSYNTHESIS; DASYPYRUM VILLOSUM; ENZIMAS; ENZYME; ENZYMES; FREE RADICALS; Fundamental and applied biological sciences. Psychology; HELIANTHUS ANNUUS; INHIBICION; INHIBITION; L-GALACTONO-GAMMA-LACTON-DEHYDROGENASEAKTIVITAET; L-galactono-γ-lactone; L-galactono-γ-lactone dehydrogenase; LACTUCA SATIVA; LUPINUS ALBUS; LYCORINE; Metabolism; PISUM SATIVUM; Plant physiology and development; RADICAL LIBRE; RADICALES LIBRES; VICIA FABA; Vicia faba L; ZEA MAYS; Zea mays L; Vicia faba L; ASC; L-galactono-γ-lactone; lycorine; GL; L-galactono-γ-lactone dehydrogenase; ascorbate biosynthesis; DHA; AFR; Zea mays L; Monocotyledones; Ascorbic acid; Glutathione dehydrogenase (ascorbate); Zea mays; Enzyme; L-Ascorbate peroxidase; Galactonolactone dehydrogenase; Vicia faba; Metabolism; Alkaloid; Monodehydroascorbate reductase (NADH); Leguminosae; Peroxidases; Enzymatic activity; Gramineae; Dicotyledones; Angiospermae; Spermatophyta; Oxidoreductases; Inhibition
• ISSN: 0176-1617; 1618-1328
• DOI: 10.1016/S0176-1617(97)80134-4

In vivo conversion of L-galactono-γ-lactone to ascorbate is carried out in all of the plants that we have analysed. The enzyme catalysing this reaction, i.e. L-galactono-γ-lactone dehydrogenase, which appears to be localised in the mitochondrial membrane, is strongly inhibited by lycorine: 5 μM lycorine almost completely inhibits the activity of the enzyme. The alkaloid does not affect the activity of the ascorbate free radical reductase, dehydroascorbate reductase or ascorbate peroxidase. The results presented here confirm that lycorine is a specific inhibitor of ascorbate biosynthesis in plants, and, consequently, that it can be a useful tool to bener understand the ascorbate metabolism in ascorbate synthesising organisms.