The Chemistry of the Bohr Effect

Abstract

SUMMARY An investigation of hemoglobin H which consists of four 0” polypeptide chains showed that : 1. The number of reactive SH groups is two per @ chain (i.e. eight per mole), although the same j3 chains in hemoglobin A contain only o?ze reactive -SH group per chain. 2. Hemoglobin H has no Bohr effect. 3. Its oxygen affinity is approximately 10 times that of hemo- globin A and its oxygen dissociation curve shows no evidence of heme-heme interaction. This behavior is duplicated by hemoglobin A in 6 M urea as shown by Rosi-Fanelli et at. 4. It is concluded that interactions between (Y and @ chains are essential for the normal oxygen affinity of hemoglobin A as well as for the variation of this parameter with oxygenation and pH value. Acknowledgnwnts-The authors are grateful to Drs. Paul Beznikoff and Ralph Engle who referred patient N. H. for study, and to Mr. Anatol Morel1 who suggested the ultrafiltra- tion method. This work was supported by grants from the National Science Foundation, and the National Heart Institute (H-2733), United States Public Health Service; by Grant A-4592 from the National Institute of Arthritis and Metabolic Diseases, United States Public Health Service, and by Grant (Contract U-1039) from the Health Research Council of New York City. REFEREXCES