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

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 k cat /K m values of 2.54×10 7 , 6.73×10 6 , 2.65×10 5 , and 3.31×10 3 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.

Plant Copper Metalloenzymes As Prospects for New Metabolism Involving Aromatic Compounds

“…Amine oxidases catalyze the deamination of primary amines and diamines to aldehydes by consumption of molecular oxygen and water with release of ammonia and hydrogen peroxide ( Solomon et al, 2014 ). Copper-containing amine oxidases (CuAOs) have faster turnover and higher affinity for putrescine and cadaverine as substrates, and with less specificity spermidine and spermine ( Padiglia et al, 1998 ; Agostinelli et al, 2005 ; Poonpipatgul, 2012 ; Tavladoraki et al, 2016 ; Zhang et al, 2016 ). Apoplastic CuAO can also oxidize long chain aliphatic and aromatic monoamines, e.g., 2-phenylethylamine and tyramine, in vitro ( Zarei et al, 2015 ).…”