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Purification and characterization of amine oxidase from Vigna mungo L. seedlings


Sunisa Poonpipatgul
Pramvadee Y. Wongsaengchantra
Suchat Udomsopagit
Jirundon Yuvaniyama

Abstract

Amine oxidases (AO) are a group of enzymes that catalyze oxidative deamination of various amines and thus are of potential use in analytical applications. Amine oxidase from five-day-old Vigna mungo L. seedlings (VAO) was purified using ammonium sulfate fractionation and Q-Sepharose chromatography to 544 purification folds with 65% yield. VAO apparently is a homodimer with denatured molecular weight of 73 kDa. This enzyme is relatively stable in a pH range of 6.0 to 8.0 and at temperature below 40°C with a complete activity loss upon storage at pH 4.0 or temperature over 60°C (1 h). Kinetics studies of VAO with putrescine, cadaverine, histamine, and tyramine showed kcat/Km values of 2.54×107, 6.73×106, 2.65×105, and 3.31×103 M–1 s–1, respectively, with undetectable catalytic activity toward tryptamine. VAO was partially inhibited by ethylenediaminetetraacetic acid (EDTA) and completely inhibited by phenylhydrazine, suggesting it is likely a member of copper-containing AO family.

Key words: Amine oxidase, cadaverine, histamine, putrescine, tyramine, tryptamine, Vigna mungo L.


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eISSN: 1684-5315