AMINO-ACIDS AND PEPTIDES .232. CHOLECYSTOKININ HEPTAPEPTIDE ANALOGS WITH MULTIPLE MODIFICATION IN PEPTIDE-CHAIN

Using solid phase synthesis we prepared the cholecystokinin fragment B oc-CCK-7 (Boc-Tyr(SO3-Na+)-Met-Gly-Trp-Met-Asp-Phe-NH2) Ia and its sev en analogues Ib - Ih. In the analogues Ib and Ic the Met residue in th e carboxyterminal part of the molecule was substituted for L- or D-Phe Me3. In the analogues Id and le with Phe residue substituted by L- or D-PheMe3 the Neo was inserted in the place of this Met residue and in the analogues If and Ig, in addition to PheMe3 substitution in the car boxyterminus, both Met residues were replaced for Neo. This dual subst itution for Met residues was also applied in the analogue Ih with code d Phe residue in the C-terminus.