The study of human serum transferrin

Abstract

In this work a chemical affinity column (DEAE-Sephadex Anion Exchanger) with disodium catechol disulphonate as an iron chelator has been used to separate iron that is tightly bound to transferrin in human serum. The results show that all iron tightly bound to transferrin was eluted with bicarbonate-chloride solution at pH 8, and the loosely bound or free iron was retained in the column. The above procedure has been used previously by other workers who have assumed that total serum iron (including loosely bound iron) is eluted with transferrin, contrary to the finding in the present investigation. To determine the total and tightly bound iron in transferrin, atomic absorption was found to be the most convenient and accurate method. Ferrozine method was slow to equilibrate and was subjected to the interference by serum proteins. The ammonium tartrate hastened colour development but the turbidity in the solutions created problems. The isosbestic point of transferrin at 290 nm reported by some previous workers has been shown to be an artifact caused by light scattering of the ultraviolet cuvette. An analytical method for estimating total iron and tightly-bound transferrin iron has been developed and applied to serum samples, from which distinct sex differences are observed.