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Abstract Erythropoiesis in the chick involves the synthesis of multiple hemoglobins. The hemoglobins found in the late embryo and in the adult chicken are called hemoglobins A and D, and the hemoglobins found in the early chick embryo are called hemoglobins E, P, and M. We have determined the peptide chain composition of the embryonic hemoglobins E and P. During the chromatographic separation of hemoglobins E and P from the red cell lysate of a 5-day embryo, a previously unsuspected hemoglobin (M) was discovered which appears to be present also in 7-day embryos. Using rabbit antisera against hemoglobins A and D, it was found that hemoglobin E was very similar antigenically to A and that hemoglobins M and D were also related, although not as closely as hemoglobins E and A. Comparison of peptide maps of the S-aminoethylated globins of A, D, E, P, and M confirmed these relationships. Hemoglobin E appears to contain the αa chain of hemoglobin A, while the peptide map of the other (e) chain bears some resemblance to that of the β chain of adult hemoglobin A. An amino acid analysis of A globin and its individual chains and of E globin and its individual chains confirmed that the α chains of hemoglobins A and E are very similar, if not identical, while the e and β chains of these two hemoglobins differ. Hemoglobin P is composed of two closely related α-like chains, π and π', and a β-like chain, ρ. The ρ and the e chain share many common peptides on their peptide maps. Hemoglobin M contains the αd chain found in hemoglobin D, while the β-like chain of hemoglobin M resembles the e chain of hemoglobin E.
Brown et al. (1974) studied this question.