An Iron–Copper–Nucleoprotein Complex in Animal Tissue

Abstract

IN the course of investigations on the availability of iron in fish and other animal tissues, it appears that a more correct figure for the nutritionally available iron would be obtained if the tissue is treated with 10 per cent acetic acid or digested with pepsin before the material is assayed by Hill's dipyridyl method. Further work has shown that 30–40 per cent of the total non–hæmin iron of several animal tissues consists of an iron–copper–nucleoprotein complex, which has been obtained in a fairly pure state. The copper seems to be loosely combined; it is easily split off by trichloroacetic acid and also by alkali. The iron is also split off by alkali. Controlled experiments with anæmic rats on hæmoglobin–building indicate that this complex (or rather its breakdown products, after absorption) may be a precursor for the formation of hæmoglobin. Previous elimination of copper from this complex has been found to diminish its hæmopoietic power. Quantities of iron and copper corresponding to a given quantity of the complex, when fed to animals, have considerably less potency regarding hæmoglobin formation than the original complex, which would indicate the importance of the organic moiety for hæmoglobin building.