title: [B-chain shortening of matrix-bound insulin by pepsin, I:Preparation and properties of bovine des-pentapeptide(B26-30) insulin (suthor's transl)].
abstract: Insulin was adsorbed to a strongly acidic ion exchanger and incubated with pepsin. The digestion of the matrix-bound insulin was found to be restricted to the cleavage of the peptide bond between phenylalanine-B25 and tyrosine-B26. Factionation of the reaction products was achieved by gel filtrationon Sephadex G-50 at pH 8 where des-pentapeptide(B26-30)-insulin does not aggregate. Another way to purify this compound was ion-exchange chromatography, which was easy due to the loss of one positive charge on the modified insulin. Crystallization could be achieved in a phenol-containing buffer. Des-pentapeptide(B26-30)-insulin was found to be molecularly uniform by electrophoresis at pH 2.2 and 8.6, thin-layer chromatography, performic acid oxidation, end group analysis and amino acid analysis. The CD-spectrum indicated conformational changes compared to insulin. The biological activity was considerably reduced: fat cell assay 20%, blood sugar depression 30%.
mesh_terms: D000818:Animals; D001665:Binding Sites; D002417:Cattle; D002942:Circular Dichroism; D003460:Crystallization; D006863:Hydrogen-Ion Concentration; D007328:Insulin / Q000031:analogs & derivatives*; D009842:Oligopeptides / Q000302:isolation & purification; D010434:Pepsin A; D010649:Phenylalanine; D011485:Protein Binding; D011487:Protein Conformation; D014443:Tyrosine
chemical_list: D007328:Insulin; D009842:Oligopeptides; D014443:Tyrosine; D010649:Phenylalanine; D010434:Pepsin A
vernacular_title: B-Kettenverkürzung von polymergebundenem Insulin mit Pepsin, I. Darstellung und Eigenschaften von Des-Pentapeptid (B26-30)-Rinderinsulin.