Structural characterization of human erythropoietin.

Erythropoietin is the primary regulator of red blood cell formation in mammals. Because of its extreme scarcity, very little information is available regarding structural features of this important glycoprotein. We report here the primary structure of human urinary erythropoietin, determined by protein sequencing. In addition, the sites of glycosylation, assignment of disulfide bonds, and the circular dichroism of the hormone analyzed for secondary structure in comparison with the prediction from the sequence are presented.