Standardization of serum ceruloplasmin concentrations in international enzyme units with o dianisidine dihydrochloride as substrate

Abstract

A method for calculating the absorptivity (in terms of substrate consumed) of the colored solution obtained when o-dianisidine dihydrochloride is oxidized by ceruloplasmin is described. By oxidizing o-dianisidine dihydrochloride with known amounts of hydrogen peroxide, one can determine that the molar reacting ratio of o-dianisidine to hydrogen peroxide is 2:1. So calculated, absorptivity is 9.6 ml μmol-1 cm-1, the figure used to estimate ceruloplasmin oxidase activity in terms of International Units.