Hemoglobins of an amphibia, the neotenous Ambystoma mexicanum. Complete amino-acid sequence of the alpha chain of the major component using automatic solid-phase Edman degradation.

The primary structure of axolotl (neotenous Ambystoma mexicanum) alpha chain has been determined. NH2-terminal sequence data were performed using the solid-phase method. Complete amino acid assignments were deduced from the sequences of peptides obtained after cleavage with cyanogen bromide; the methionine-containing peptides, isolated from alpha chain tryptic digest, allowing the alignment of these fragments. All overlaps have been clearly established. Axolotl alpha chain contains 142 residues, one extra phenylalanine residue being located at its N terminus, when compared with mammalian alpha chains. The amino acid sequences of this polypeptidic chain and of an other urodele, the newt Taricha granulosa, show 44 differences with only 18 non-isopolar replacements. Homologies between various vertebrate alpha chains are briefly discussed.