Studies on Haptoglobin. II

Combining ability of antihuman hemoglobin antibody and human haptoglobin with various hemoglobins was tested. Antihuman hemoglobin antibody can combine and precipitate with deoxygenated hemoglobin A1 and hemoglobin-haptoglobin complex with both of which human haptoglobin cannot combine. On the other hand, antihuman hemoglobin antibody cannot combine with hemoglobins of other species with which human haptoglobin can combine. From these observations it is suggested that binding site and mechanisms of antihuman hemoglobin antibody with hemoglobin differ from those of human haptoglobin with hemoglobin.