Ultracentrifugal behavior of transferrin in the presence of some anions

Abstract

Transferrin of pooled human plasma has been found to aggregate reversibly in the presence of BrO₃⁻, IO₃⁻, SCN⁻, Cl⁻, Br⁻, I⁻, and NO₃⁻, giving weight-average sedimentation coefficients of from 5·50 S to 6·83 S compared to a normal s_20,w of 5·10 S at 0·7% concentration. The aggregation was most pronounced in the vicinity of the isoelectric points of transferrin, i.e. at pH 5·0, and was dependent on the anion, but not on the protein concentration. No aggregation was observed in the presence of acetate, formate, chloroacetate, fluoride, cacodylate and sulfate at any pH value.