Catalyzes an oxidative deamination of predominantly hydrophobic and aromatic L-amino acids, thus producing hydrogen peroxide that may contribute to the diverse toxic effects of this enzyme (PubMed:22963728). Is highly active on L-Met=L-Leu>>L-Phe>L-Trp>L-Tyr>L-Ile, and weakly or not active on L-His, L-Arg, L-Val, L-Gln, L-Thr, L-Lys, and L-Ser (PubMed:22963728). Exhibits a low myotoxicity (a mild myonecrosis is observed after injection in mice quadriceps muscle) (PubMed:22963728). In vitro, is cytotoxic to a lot of human cell lines, including AGS (IC(50)=22.7 ug/ml), MCF-7 (IC(50)=1.4 ug/ml), HL-60, HeLa and Jurkat cells, as well as to the parasite Leishmania brasiliensis (IC(50)=2.22 ug/ml) (PubMed:22963728). This cytotoxicity is dependent on the production of hydrogen peroxyde, since it is inhibited by catalase, a hydrogen peroxyde scavenger (PubMed:22963728). an L-alpha-amino acid + H2O + O2 = a 2-oxocarboxylate + H2O2 + NH4(+) H2O + L-leucine + O2 = 4-methyl-2-oxopentanoate + H2O2 + NH4(+) H2O + L-phenylalanine + O2 = 3-phenylpyruvate + H2O2 + NH4(+) H2O + L-tryptophan + O2 = H2O2 + indole-3-pyruvate + NH4(+) H2O + L-methionine + O2 = 4-methylsulfanyl-2-oxobutanoate + H2O2 + NH4(+) H2O + L-isoleucine + O2 = (S)-3-methyl-2-oxopentanoate + H2O2 + NH4(+) H2O + L-tyrosine + O2 = 3-(4-hydroxyphenyl)pyruvate + H2O2 + NH4(+) Optimum pH is 8.0 for L-Leu. Optimum temperature is 4 degrees Celsius. Homodimer; non-covalently linked. Expressed by the venom gland. This enzyme does not cause hemorrhage, paw edema morphological changes of heart, lung and kidney when injected into mice. Is not toxic to the parasite Trypanosoma cruzi. Belongs to the flavin monoamine oxidase family. FIG1 subfamily.