Isolation of an Iron-Containing Red Protein from Human Milk.

Abstract

After the addition of Fe++ to human skim-milk, various protein fractions were removed by precipitation at pH 8.0 and 37°C, in the presence of (NH4)2SO4, followed by precipitation at pH 4.0 with IM H2SO4. The separation of the red protein from the resulting supernatant was accomplished by precipitation at pH 8.0, after the addition of (NH4)2SO4, by dialysis and chromatography on DEAE-cellulose. Electrophoretic and light absorption studies were carried out on the fraction. The concentration of Fe was found to be 0.13-0.15% and little was removed at pH 8.5 with Dowex 50. Studies suggest that the fraction is similar, but not identical, to blood serum transferrin. M.P.H.