Cholecystokinin 12 (CCK12)

Since its discovery in the brain, anatomical, physiological and pharmacological research on cholecystokinin (CCK) and its possible involvement in neurological and psychiatric disease has continued unabated. The chemical synthesis of sulfated CCK12 was reported by Ondetti and co-workers at Squibb (115) in 1970. They provided synthetic CCK 8 to investigators for years until it became commercially available in the early 1980s. The synthesis of CCK is complicated by the difficulty and low efficiency of the addition of the sulfate group to the tyrosine after conventional peptide synthesis with t-boc (t-butyloxycarbonyl) amino acids. Recent improvements in peptide synthesis, in which the sulfated tyrosine is incorporated into the peptide backbone as an FMOC (9-fluorenyl-methoxycarbonyl) amino acid, has allowed the synthesis of human and porcine CCK 33 (119) and canine CCK 58.