On the mechanism and rate of substrate oxidation by amine oxidase from lentil seedlings

• Published in: The Journal of biological chemistry Vol. 266; no. 31; pp. 20654 - 20657
• Main Authors: Bellelli, A., Agro, A.F., Floris, G., Brunori, M.
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Elsevier Inc 05.11.1991; American Society for Biochemistry and Molecular Biology
• Subjects: actividad enzimatica; activite enzymatique; aminas biogenicas; amine biogene; Amine Oxidase (Copper-Containing); Analytical, structural and metabolic biochemistry; Benzylamines - metabolism; biogenic amines; Biological and medical sciences; dimethylaminomethylbenzylamine; Enzymes and enzyme inhibitors; enzymic activity; espectrometria; Fabaceae - enzymology; Fundamental and applied biological sciences. Psychology; Kinetics; Lens culinaris; Oxidoreductases; Oxidoreductases Acting on CH-NH Group Donors - metabolism; Plants, Medicinal; plantulas; plantule; putrescine; Putrescine - metabolism; seedlings; spectrometrie; spectrometry; Spectrum Analysis; Vegetals; Monoamine oxidase; Leguminosae; Enzyme; Dicotyledones; Angiospermae; Reaction mechanism; Spermatophyta; Oxidation; Kinetics; Lens culinaris
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(18)54758-X

The kinetics of reaction between lentil seedlings amine oxidase and two amine substrates, namely putrescine and dimethylaminomethylbenzylamine, have been studied by rapid mixing with diode array detection. In this way several wavelengths can be monitored at once allowing the simultaneous measurement of enzyme bleaching and formation of a yellow radical intermediate. The two substrates are oxidized at rates that differ by one order of magnitude in favor of putrescine. Of the individual five rate constants measured and/or calculated from the experimental ones, k2 alone, the monomolecular transformation of ES to EP accounts for this difference. The reoxidation step is instead not rate limiting and identical for the two substrates.