Studies on copper metabolism. XXVII. The isolation and properties of an erythrocyte cuproprotein (erythrocuprein).

In 1924, Hart, Elvehjem and coworkers demonstrated that copper is essential for erythropoiesis in most, if not all, mammalian species (1). Since that time many studies have been performed in attempts to elucidate the manner in which copper functions in erythropoiesis, but as yet this mechanism is not understood. Recent studies in this laboratory (2) have indicated that the amount of copper in the erythrocytes of copper-deficient pigs is reduced and that the life span of these copper-deficient erythrocytes in the circulation is shortened. This suggests that copper may be an essential component of adult red cells and, therefore, it seemed of importance to isolate and characterize the copper‘containing component or components of erythrocytes. The only previous study of this nature was that of Mann and Keilin (3). These workers isolated a blue copper protein from ox erythrocytes. The protein contained 0.34 per cent copper and had a molecular weight of about 34,000. Attempts to isolate a pure copper protein from human erythrocytes were unsuccessful, although a preparation containing 0.21 per cent copper was obtained. The purpose of this paper is to describe the isolation of a copper protein from human erythrocytes and to outline an immunologic technique for the quantitative estimation of this protein in hemolysates of erythrocytes. In addition, immunologic, chemical and physical properties of the protein are described in this and in another paper (4).