The Structure of Goat Hemoglobins

Abstract

Abstract Partial amino acid sequences of the α chains of goat hemoglobins A and B have been determined by fragmentation of the polypeptide chains and their insoluble cores with trypsin and chymotrypsin. The α chain of hemoglobin A was found to consist of two distinct polypeptides, which differ in at least 4 amino acid residues, located in positions 19 and 26 and between positions 113 and 115. One chain was designated as α-A or α-(Gly-19, Ala-26, Leu-113, Asx-115) and the second as α'-A or α-(Ser-19, Thr-26, His-113, Ser-115). The α chain of hemoglobin B was found to be a variant of the α-A chain by a substitution of an aspartyl residue in position 75 for a tyrosyl residue. The α-B chain was therefore designated as α-(Gly-19, Ala-26, Tyr-75, Leu-113, Asx-115), and hemoglobin B as α275 tyrβ2. The data indicate the presence of two nonallelic, closely linked α chain structural genes in the goat, while the α-B chain is considered to be the product of an allele of one of these two structural genes.