Development of a colorimetric enzymatic assay method for aromatic biogenic monoamine-producing decarboxylases

Abstract

Biogenic amines (BAs) produced by the action of bacterial amino acid decarboxylases in fermented foods cause various health problems in human. Despite the importance, detailed characterizations of the BA-producing decarboxylases are relatively less progressed than the studies on BA-producing bacteria, due to the time-consuming chromatography-based assay method. In this study, a simple and general colorimetric assay for aromatic amino acid decarboxylases coupled with an amine oxidase from Arthrobacter aurescens (AMAO) and horseradish peroxidase was developed using a tyrosine decarboxylase from Enterococcus faecium DSM20477 (EfmTDC) as a model enzyme. The activity profiles over pH and temperature and the kinetic analysis for EfmTDC revealed that the results by the colorimetric assay are compatible with those by the chromatographic assay. In addition, due to the broad substrate specificity of AMAO for histamine and 2-phenylethylamine, the colorimetric assay would be applicable to the characterization of other aromatic amino acid decarboxylases including histidine decarboxylases.