Synthesis and biological activities of cholecystokinin analogues substituted in position 30 by 3-(1-naphthyl)-l-alanine [Nal(1)] or 3-(2-naphthyl)-l-alanine [Nal(2)]
摘要:
Acetyl derivatives of ethyl esters of 3-(1-naphthyl)-D,L-alanine and 3-(2-naphthyl)-D,L-alanine were synthesized through a malonic condensation. Resolution of these derivatives by subtilisin Carlsberg followed by acid hydrolysis afforded the 2 optical isomers of 3-(1-naphthyl)-alanine [Nal(1)] and 3-(2-naphthyl)-alanine [Nal(2)]. The L enantiomers of these amino acids were incorporated into the sequence of cholecystokinin in place of the tryptophan in position 30. The cholecystokinin analogues thus obtained behaved as full agonists, with reduced potencies on rat pancreatic acini and on guinea pig brain membranes, by about one order of magnitude for the Nal(2) derivative and by 2 orders of magnitude for the Nal(1) derivative, as compared to the potent parent compound Boc-Tyr(SO3H)-Nle-Gly-Trp-Nle-Asp-Phe-NH2.
Syntheses of some partiallymodifiedretro-inverso analogues of the C-terminal octa- or heptapeptide of cholecystokinin are described. These analogues (in which the C-terminal carboxamide was deleted or not) were obtained by reverting one or several peptide bonds in the parent molecule. All these compounds were able to inhibit binding of labeled CCK-8 to rat pancreatic acini and guinea pig brain membranes
Synthesis and biological evaluation of cholecystokinin analogs in which the Asp-Phe-NH2 moiety has been replaced by a 3-amino-7-phenylheptanoic acid or a 3-amino-6-(phenyloxy)hexanoic acid
Boc-Tyr(SO3H)-Nle-Gly-Trp-Nle-Asp-2-phenylethyl ester (JMV180), an analog of the C-terminal octapeptide of cholecystokinin (CCK-8), shows interesting biological activities behaving as an agonist at the high-affinity CCK binding sites and as an antagonist at the low-affinity CCK binding sites in rat pancreatic acini. Although we did not observe any major hydrolysis of the ester bond of Boc-Tyr(SO3H)-Nle-Gly-Trp-Nle-Asp-2-phenylethyl ester in our in vitro studies, we were aware of a possible and rapid cleavage of this ester bond during in vivo studies. To improve the stability of Boc-Tyr(SO3H)-Nle-Gly-Trp-Nle-Asp-2-phenylethyl ester, we decided to synthesize analogs in which the ester bond would be replaced by a carba (CH2-CH2) linkage. We synthesized the 3-amino-7-phenylheptanoic acid (beta-homo-Aph) with the R configuration in order to mimic the Asp-2-phenylethyl ester moiety and the 3-amino-6-(phenyloxy)hexanoic acid (H-beta-homo-App-OH), an analog of H-beta-homo-Aph-OH in which a methylene group has been replaced by an oxygen. (R)-beta-Homo-Aph and (R)-H-beta-homo-App-OH were introduced in the CCK-8 sequence to produce Boc-Tyr(SO3H)-Nle-Gly-Trp-Nle-(R)-beta-homo-Aph-OH and Boc-Tyr(SO3H)-Nle-Gly-Trp-Nle-(R)-beta-homo-App-OH. Both compounds were able to recognize the CCK receptor on rat pancreatic acini (IC50 = 12 +/- 8 nM and 13 +/- 5 nM, respectively), on brain membranes (IC50 = 32 +/- 2 nM and 57 +/- 5 nM, respectively), and on Jurkat T cells (IC50 = 75 +/- 15 nM and 65 +/- 21 nM, respectively). Like Boc-Tyr(SO3H)-Nle-Gly-Trp-Nle-Asp-2-phenylethyl ester, both compounds produced maximal stimulation of amylase secretion (EC50 = 6 +/- 2 nM and 4 +/- 2 nM, respectively) with no decrease of the secretion at high concentration indicating that these compounds probably act as agonists at the high-affinity peripheral CCK-receptor and as antagonists at the low-affinity CCK-receptor. Replacing the tryptophan by a D-tryptophan in such analogs produced full CCK-receptor antagonists. All these analogs might be more suitable for in vivo studies than Boc-Tyr(SO3H)-Nle-Gly-Trp-Nle-Asp-2-phenylethyl ester.
RODRIGUEZ, MARC;GALAS, MARIE-CHRISTINE;LIGNON, MARIE-FRANCOISE;MENDRE, CH+, J. MED. CHEM., 32,(1989) N0, C. 2331-2339