Enzymatic synthesis of a CCK-8 tripeptide fragment in organic media

✍ Scribed by M. Capellas; M. D. Benaiges; G. Caminal; G. Gonzalez; J. Lopez-Santín; P. Clapés

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 884 KB
• Volume: 50
• Category: Article
• ISSN: 0006-3592
• DOI: 10.1002/(sici)1097-0290(19960620)50:6<700::aid-bit11>3.0.co;2-i

✦ Synopsis

The enzymatic synthesis of the tripeptide derivative Z-Gly-Trp-Met-OEt is reported. This tripeptide is a fragment of the cholecystokinin C-terminal octapeptide CCK-8. Studies on the a-chymotrypsin catalyzed coupling reaction between Z-Gly-Trp-R, and Met-R, have focused on low water content media, using deposited enzyme on inert supports such as Celite and polyamide. The effect of additives (polar organic solvents), the acyl-donor ester structure, the C-a protecting group of the nucleophile, enzyme loading, and substrate concentration were tested. The best reaction medium found was acetonitrile containing buffer (0.5%, v/v) and triethylamine (0.5%, v/v) using the enzyme deposited on Celite as catalyst (8 m g of a-chymotrypsin/g of Celite). A reaction yield of 81% was obtained with Z-Gly-Trp-OCam as acyl donor, at an initial concentration of 80 m M. The tripeptide synthesis was scaled up to the production of 2 g of pure tripeptide with an overall yield of 71%, including reaction and purification steps. 0