Kinetic assay of aldehyde oxidase with 2,2'-azino-di-(3-ethylbenzthiazoline-6-sulfonate) as chromogen.

A new kinetic method for the assay of aldehyde oxidase (EC 1.2.3.1) is described. By the oxidation of pyridoxal as a substrate, pyridoxic acid and hydrogen peroxide are formed. Hydrogen peroxide is subsequently reduced to water by the action of peroxidase, while the chromogen 2,2'-azino-di-(3-ethylbenzthiazoline-6-sulfonate) (ABTS) is oxidized to a blue-greenish-dyed product. The absorbance increase of the oxidized form of ABTS, registered every minute at 410 nm, is proportional to aldehyde oxidase activity.