Enzyme activity of LAAO

The LAAO activity was measured by the initial rate of H₂O₂ production with peroxidase/dye assay [42]. The assay mixture contained either BmLAAO or BaLAAO (2 µg), 0.01 M L-amino acid, 0.2 M Tris-HCl buffer pH 8.0, 0.2 mg/mL o-dianisidine hydrochloride, 1 U/mL horseradish peroxidase. Further, the reaction mixture was incubated at 30°C for 1 h and the dye formation was measured spectrophotometrically at 410 nm in a Varioskan™ LUX multimode microplate reader (Thermo Fisher Scientific, USA). Further, the effect of divalent metal ions (CaCl₂, ZnCl₂, MgCl₂, HgCl₂ - 10 mM each) and amino acid derivative N-acetyl cysteine (5 mM), was tested on LAAO activity using L-Leu, L-Met, L-His, L-Tyr and L-Trp as substrates by incubating for 30 minutes at 37ºC.