The main protein of enriched and purified amyloid from Octodon degus pancreatic islets was identified as insulin. The material was reduced and alkylated and the A- and the B-chain were separated by reversed phase chromatography and subjected to Edman degradation and amino acid analysis. It was shown that the A-chain contains two additional C-terminal amino acid residues (i.e. a total of 23 residues) and that the B-chain has a deletion in the C-terminal part (i.e. a total of 29 residues). The obtained sequence follows: A-chain: GIVDQCCNNICTFNQLQNYCNVP B-chain: YSSQHLCGSNLVEALYMTCGRSGFYRPHD.