Studies on Monotreme Proteins. IV Amino Acid Sequence of Haemoglobin-IA of the Echidna; A Comparison of Major Haemoglobins From Two Geographical Groups of Echidnas

Abstract

The amino acid sequences of the ex-and fJ-chains from a major haemoglobin (Hb-IA) of an echidna geographically isolated from those animals previously studied have been determined. The fJ-chain of Hb-IA was identical in amino acid sequence with the fJ-chain in Hb-IB. The ex-chain of Hb-IA varied in four positions from that in Hb-IB, and had one more acidic group, in line with the higher electro-phoretic mobility of Hb-IA at pH 8· 5. There were no differences in 'contact site' residues in the ex-chains of the two haemoglobins.