Purification and Properties of Phenylethylamine Oxidase ofArthrobacter globiformis

Phenylethylamine oxidase (EC class 1.4.3) of Arthrobacter globiformis IFO 12137 (ATCC 8010) was purified to homogeneity. The enzyme had a Mr of 141,000 and was composed of two apparently identical subunits, which had a Mr of 71,000 and contained one copper ion. The absorption spectrum of the enzyme had maxima at 280 and 480nm, and the ratio A280/A480 was 61.5. Hydrogen peroxide was formed in the oxidation of amines. The enzyme was most active and stable at pH 6.5. 2-Phenylethylamine and tyramine were the most active substrates. Several aromatic monoamines, aliphatic monoamines with 4–11 carbons, higher aliphatic diamines, and histamine were poor substrates. Benzylamine, putrescine, spermine, and spermidine were not oxidized. The Kms for 2-phenylethylamine and tyramine were 18 and 85 μm, and the Vmaxs for them were 27.1 and 26.4μmol/min/mg of enzyme, respectively. Benzyl alcohol was a noncompetitive and benzylamine was a mix-type inhibitor of the enzyme. Carbonyl-blocking reagents such as methylhydrazine, ...