Proteolytic degradation of hemoglobin in erythrocytes leads to biologically active peptides.

A number of hemoglobin-derived homogeneous peptides were isolated from erythrocyte lysate. The amino acid sequences of nine peptides were determined. Seven out of nine peptides were relatively long, 30-32 membered peptides covering the N- or C-terminal sequences of globin chains. The remaining two were the pentapeptide neo-kyotorphin and its tetrapeptide derivative.