The enzymatic synthesis of a tetrapeptide Phac-Met-Gly-Trp-Met-OEt, a fragment of the cholecystokinin C-terminal octapeptide CCK-8, was reported. This fragment was synthesized by coupling Phac-Met-OEt with Gly-OMe, Trp-OMe and Met-OEt successively. These three steps were catalyzed by alpha-chymotrpsin, Papain and alpha-chymotrpsin respectively. The results of FAB-MS showed that all the products had the correct molecular mass.
Catalysis ; Chymotrypsin ; *Oligopeptides ; Papain ; Peptide Fragments ; Sincalide/*chemical synthesis

The synthesis of CCK-4 (H-Trp-Met-Asp-Phe-NH2) by using enzymes exclusively was described. As protection group for the amino group we used the Phenylacetyl group (Phac) which had been cleaved at the end of the synthesis with Penicillin G Amidase (PGA) without affecting the peptide bonds. Thus, beginning with Phac-Trp-OH we had successfully synthesized the target peptide with following 4 enzymes, alpha-Chymotrypsin, Papain, Thermolysin and PGA in four reaction steps. All reactions were carried out in aqueous buffer in reasonable yields (> 65%). FAB-MS or FD-MS verified the correct molecular mass of all peptides.
Chymotrypsin ; Enzymes, Immobilized ; Papain ; Peptides ; Tetragastrin/*chemical synthesis ; Thermolysin

The enzymatic synthesis of a tetrapeptide Phac-Met-Gly-Trp-Met-OEt, a fragment of the cholecystokinin C-terminal octapeptide CCK-8, was reported. This fragment was synthesized by coupling Phac-Met-OEt with Gly-OMe, Trp-OMe and Met-OEt successively. These three steps were catalyzed by alpha-chymotrpsin, Papain and alpha-chymotrpsin respectively. The results of FAB-MS showed that all the products had the correct molecular mass.
Catalysis ; Chymotrypsin ; Oligopeptides ; Papain ; Peptide Fragments ; Sincalide ; chemical synthesis

The synthesis of CCK-4 (H-Trp-Met-Asp-Phe-NH2) by using enzymes exclusively was described. As protection group for the amino group we used the Phenylacetyl group (Phac) which had been cleaved at the end of the synthesis with Penicillin G Amidase (PGA) without affecting the peptide bonds. Thus, beginning with Phac-Trp-OH we had successfully synthesized the target peptide with following 4 enzymes, alpha-Chymotrypsin, Papain, Thermolysin and PGA in four reaction steps. All reactions were carried out in aqueous buffer in reasonable yields (> 65%). FAB-MS or FD-MS verified the correct molecular mass of all peptides.
Chymotrypsin ; Enzymes, Immobilized ; Papain ; Peptides ; Tetragastrin ; chemical synthesis ; Thermolysin