THE PRIMARY STRUCTURE OF GLUCAGONLIKE PEPTIDE BUT NOT INSULIN HAS BEEN CONSERVED BETWEEN THE AMERICAN EEL, ANGUILLA-ROSTRATA AND THE EUROPEAN EEL, ANGUILLA-ANGUILLA

Insulin was isolated from the pancreas of the American eel, Anguilla rostrata, and its primary structure was established as {A figure is presented} Eel insulin contains unusual substitutions at B-21, B-22, and B-26 in the putative receptor-binding region of the molecule compared with other mammalian and fish insulins. The A-chain of insulin from the European eel contains an asparagine rather than a serine residue at position A-12. Similarly, amino acid composition data indicate the B-chain of insulin from the European eel is appreciably different from that from the American eel. The primary structure of glucagon-like peptide (GLP) from the American eel is identical to that from the European eel, Anguilla anguilla. The primary structure of the peptide was established as {A figure is presented} Fast-atom bombardment mass spectrometry demonstrated that the COOH-terminal arginyl residue is α-amidated. The strong evolutionary pressure to conserve the structure of GLP provides further support for the assertion that the peptide plays an important regulatory role in teleost fish. © 1991.