title: Trypsin as a catalyst for peptide synthesis.
abstract: Trypsin-catalyzed syntheses of peptides were performed using various N-acylated amino acid or peptide esters as donors and amino acid derivatives, peptides, or their derivatives as acceptors. The synthesis was almost quantitative under optimal conditions. Considerably more enzyme and a more alkaline pH were necessary for synthesis than hydrolysis. Another very important condition was the concentration of the starting materials; higher concentrations resulted in much better product yields. The nucleophile specificity for synthesis was also important; hydrophobic or bulky amino acid residues were most efficient at the P1' position, and L-proline as well as D-amino acid residues were the worst choices. The synthesis was also dependent on the solubility of the products synthesized; the yield was higher with products of lower solubility. As donor esters, good substrates were all useful. Accordingly, fragment condensation was possible using N-acylated peptide esters and various peptides. The present study suggests that trypsin may become a useful tool for peptide synthesis.
mesh_terms: D000818:Animals; D002417:Cattle; D007700:Kinetics; D010452:Peptide Biosynthesis; D013329:Structure-Activity Relationship; D013379:Substrate Specificity; D014357:Trypsin / Q000378:metabolism*
chemical_list: D014357:Trypsin