title: Evidence for peptide synthesis in the course of in vitro proteolysis.
abstract: The present paper reports on studies concerned with furnishing evidence for peptide synthesis in the course of in vitro proteolysis. To this end, the oxidized chain B from insulin (INS) (S = 5% in demineralized water) was subjected to tryptic proteolysis (E/S = 1/50; pH 5; 37 degrees C; 24 h). HPLC-as well as amino acid-and sequence analytical studies have shown that the heptapeptide INS 23-29 (Gly-Phe-Phe-Tyr-Thr-Pro-Lys) liberated by way of hydrolysis is linked by tryptic synthesis via transpeptidation or condensation to form a dimer which accounts for 15% of the amount of monomer. The results of the model trials show clearly that during in vitro proteolysis chemical reactions beyond hydrolytic cleavage of peptide bonds take place. In principle, plastein-like reactions (transpeptidation, condensation) can occur during each in vitro proteolysis.
authors.affiliation: Institute for Chemistry and Physics, Federal Dairy Research Centre, Kiel, Germany.
authors.forename: P
authors.initials: P
authors.lastname: Lorenzen
authors.forename: A
authors.initials: A
authors.lastname: Goepfert
authors.forename: A
authors.initials: A
authors.lastname: Schieber
authors.forename: H
authors.initials: H
authors.lastname: Brückner
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D006868:Hydrolysis; D007328:Insulin / Q000737:chemistry*; D008969:Molecular Sequence Data; D010455:Peptides / Q000138:chemical synthesis*; D014357:Trypsin / Q000737:chemistry*
chemical_list: D007328:Insulin; D010455:Peptides; D014357:Trypsin