Amino acid differences between the alpha-chains from two hemoglobins of the yellow-cheeked vole (Family Cricetidae).

The yellow-cheeked vole (Microtus xanthognathus) shows two electrophoretic hemoglobin components. Electrophoresis of the polypeptide chains from the separated hemoglobin components shows identical beta-chains but two alpha-chains of different mobility, alphaf and alphas. The composition of soluble tryptic peptides was determined for each alpha-chain. Amino acid differences were found in peptides alpha T1 and alpha T9; the compositions of the remainder of the homologous peptides were identical. Differences in alpha T1, found at alpha4 (alpha2-Gly-alphaf-Val) and alpha 5 (alphas-Thr-alphaf-Asp), were confirmed after a run to residue 20 of the fast component in an automatic sequencer. The differences in charge between alphaT1 peptides can account for the electrophoretic pattern of two hemoglobins. This is the first time that it has been possible to identity the residues which can account for the charge difference between the two hemoglobins observed in a Microtus species.