Two new mutant hemoglobins, each with abnormal α-chains, have been found along with normal adult hemoglobin in three brothers of a Hungarian family. Preliminary identification of the abnormal chains and genetic studies have been reported earlier (Hollán, S. R., Szelenyi, J. G., Brimhall, B., Duerst, M., Jones, R. T. Koler, R. D. and Stocklen, Z. (1972) Nature 235, 47-50). The present paper reports the structural characterizations of the two abnormal α-chains found in affected members of this family and of the normal α-chain from one of the brothers who also had the two abnormal hemoglobins. One abnormal hemoglobin, named J-Buda, has a substitution of an asparaginyl residue for the lysyl residue 61 (E 10) of its α-chain. The second abnormal hemoglobin, named G-Pest, has an asparaginyl residue for the aspartyl residue 74 (EF 3) of its α-chain. The amino acid compositions of all of the other tryptic peptides of the abnormal α-chains and of all of the tryptic peptides of the normal α-chain from one of the affected brothers were identical to compositions reported for tryptic peptides of normal human α-chains. We conclude that except for the substitution of single amino acid residues in the two abnormal α-chains, the compositions and probably the sequences of amino acid residues of the four gene products from two α-chain loci are identical, at least in this Hungarian family.
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