Characterization of two amine oxidases from Aspergillus carbonarius AIU 205

We have reported that Aspergillus carbonarius AIU 205, which was isolated by our group, produced three enzymes exhibiting oxidase activity for 4-aminobutanamide (4-ABAD) (J. Biosci. Bioeng., 117, 263–268, 2014). Among three enzymes, characteristics of enzyme I have been revealed, but those of the other two enzymes have not. In this study, we purified enzymes II and III, and compared their characteristics with those of enzyme I. Enzymes II and III also oxidized aliphatic monoamines, aromatic amines, and aliphatic aminoalcohols. In addition, the oxidase activity of both enzymes was strongly inhibited by carbonyl reagents and specific inhibitors for copper-containing amine oxidases. Thus, enzymes II and III were also classified into the copper-containing amine oxidase group (EC 1.4.3.6) along with enzyme I. However, these three enzymes differed from each other in their enzymatic, kinetic, and physicochemical properties. The N-terminal amino acid sequences also differed from each other; that of enzyme I was modified, that of enzyme II was similar to those of peroxisomal copper-containing amine oxidases, and that of enzyme III was similar to those of copper-containing amine oxidases from the genus Aspergillus. Therefore, we concluded that A. carbonarius AIU 205 produced three different types of amine oxidase in the mycelia.