Iron oxidation by casein

Abstract Casein accelerates the oxidation of Fe(II) to Fe(III) and the resulting Fe(III) remains strongly bound to the casein. Removal of phosphate from the casein abolishes the oxidative process. The oxidation rate is proportional to the casein concentration, and with high casein concentrations the rate is pseudo-first-order with respect to Fe(II) with a half-life of approximately 2 minutes. The oxidized iron is stoichiometrically bound to the casein, each mg of casein binding approximately 10 μg of iron. The physiological significance is discussed.