Purification and characterization of a haptoglobin-hemoglobin complex isolated from human fetuses

A haptoglobin-hemoglobin complex was purified from human fetuses (10-week-old pregnancies). The yield was 12% and the purification factor was about 450. The purified complex appears to have a molecular weight of 850,000 daltons. It cross-reacts with human adult haptoglobins. Its electrophoretic mobility was reduced from alpha 2- to beta-globulin when compared with the adult molecule.