a-Chain Sequence of Newt Haemoglobin (Taricha granulosa)

Abstract

The amino acid sequence of the IX-chain of the major haemoglobin of a newt, T. granulosa, has been determined. The chain is 142 residues long and has an extra methionine at its N-terminus when compared with human IX-chain. Most of the tryptic peptides were sequenced by a combination of the subtractive Edman method and by deduction from the compositions of overlapping fragments produced by various enzymic treatments. The sequence of two 'core' regions was obtained by automatic sequencing of large peptides produced by trypsin cleavage at arginine residues only after blockage of lysine residues by citraconylation; by cleavage between aspartic acid and proline residues with 70% formic acid, and by cyanogen bromide cleavage at methionine residues.