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. 1979 Apr 1;179(1):183–189. doi: 10.1042/bj1790183

Action of human pepsins 1,2,3 and 5 on the oxidized B-chain of insulin.

N B Roberts, W H Taylor
PMCID: PMC1186608  PMID: 383071

Abstract

Human pepsins 1 and 2 attack the B-chain of oxidized insulin at pH 1.7 at the same bonds as does human pepsin 3. At pH 3.5, pepsins 1 and 2 attack insulin B-chain at essentially the same bonds as at pH 1.7, but more slowly. For all three enzymes, the first bond to be hydrolysed is Phe(25)-Tyr(26), followed simultaneously by Glu(13)-Ala(14), Leu(15)-Tyr(16) and Tyr(16)-Leu(17). Human pepsin 5, however, attacks Phe(24)-Phe(25) first of all, followed by Leu(15)-Tyr(16) and Tyr(16)-Leu(17). The results suggest that each pepsin has only one active site. Acid hydrolysis indicates that the sites of enzymic cleavage are not bonds with an inherent instability at low pH.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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