Differential effects of 2,3-DPG, ATP and inositol pentaphosphate (IP5) on the oxygen equilibria of duck embryonic, fetal and adult hemoglobins

Abstract

1. 1. In addition to the fetal and adult hemoglobins (F, A and D) already described in the Peking Duck, there are two embryonic hemoglobins (E 1 and E 2) which disappear by day 21 of incubation. 2. 2. Fetal hemoglobin does not exhibit any specific 2,3 DPG effect, in spite of the fact that this is the major red cell phosphorylated intermediate during the last quarter of the prehatching period. Conversely, embryonic hemoglobins are sensitive to IP5 in spite of the fact this compound is absent in the corresponding red cells. 3. 3. ATP preferentially lowers the oxygen affinity of Hb A. 4. 4. IP5 is the major organic phosphate effector with respect to oxygen affinity in vitro in all duck hemoglobins studied. 5. 5. Hb D exhibits an increased Bohr effect as compared with Hbs A and F. 6. 6. Considering the organic phosphates present at each period of development, the corresponding hemoglobin pattern, and the p50 induced by these phosphorylated compounds we suggest that there is a need for a higher oxygen affinity for the red cells during the immediate pre-hatching period and that 2,3 DPG could be the appropriate phosphate modulator for this phenomena.