Xanthine oxidase and milk flavoprotein

Abstract

in a thorough investigation, isolated a flavoprotein from cow's milk and presented evidence which rendered highly probable its identity with the xanthine-aldehyde oxidase. Corran & Green [1938, 1, 2] simultaneously isolated from the same source a flavoprotein which showed no activity as xanthinealdehyde oxidase but which could catalyse the oxidation of dihydrocoenzyme I. The recorded properties of the two flavoproteins appeared to be identical except with respect to catalytic activity. The aim of the present investigation was to determine by further purification whether there are two flavoproteins, one catalysing the oxidation of hypoxanthine and aldehyde, the other catalysing the oxidation of dihydrocoenzyme; and if there is in fact only one flavoprotein, to explain why Corran & Green were unable to find any xanthine-oxidase activity in their flavoprotein preparation.