A Sensitive Fluorimetric Assay for Human Serum Monoamine Oxidase Activity

Abstract

A sensitive fluorimetric method for the assay of human serum monoamine oxidase is described, in which benzaldehyde, formed enzymatically from the substrate benzylamine, is quantitated by means of the fluorimetric method for selective determination of aromatic aldehydes with 2, 2'-dithiobis (1-aminonaphthalene). The limit of detection for the benzaldehyde formed enzymatically is 100 pmol. This method is readily performed with good precision and a minimum amount of serum. Serum monoamine oxidase activity in patients with various thyroid diseases was assayed by this method.