- Nitrilase-catalyzed enantioselective synthesis of pyrrolidine- And piperidinecarboxylic acids
-
The enantioselective synthesis of the nonproteinogenic amino acids β-proline and nipecotic acids from their readily available nitriles is achieved in high enantiomeric excess by commercially available nitrilases. The presented procedure comprises not more than 4 steps, thus considerably reducing the multiple steps generally required. Amide formation is also observed for specific heterocyclic nitriles.
- Winkler, Margit,Meischler, Dorith,Klempier, Norbert
-
p. 1475 - 1480
(2008/09/16)
-
- Stability against enzymatic hydrolysis of endomorphin-1 analogues containing β-proline
-
The enantiomer of endomorphin-1 (Tyr-Pro-Trp-PheNH2) and the analogues containing (S)-or (R)-β-proline have been synthesized, and their affinities towards μ-opioid receptors have been measured. As expected, the incubations of the different peptides with some commercially available enzymes showed that the presence of D-residues gave strong resistance towards digestion. The presence of β-proline alone is sufficient to confer good resistance against the hydrolysis of the biologically strategic Pro-Trp bond.
- Cardillo, Giuliana,Gentilucci, Luca,Tolomelli, Alessandra,Calienni, Maria,Qasem, Ahmed R.,Spampinato, Santi
-
p. 1498 - 1502
(2007/10/03)
-
- Synthesis and binding activity of endomorphin-1 analogues β-amino acids
-
Endomorphin-1 (Tyr-Pro-Trp-PheNH2) has been proposed as the most potent endogenous ligand of the μ-opioid receptors. In this paper, we describe the synthesis of some endomorphin-1 based tetrapeptides in which a residue of the sequence Tyr-Pro-Trp-PheNH2 is replaced by the corresponding β-isomer. These novel peptides showed different affinities for the opioid receptors labeled with [3H]-DAMGO in rat brain membranes, depending on the β-amino acid. In particular, the tetrapeptide containing β-Pro (Tyr-β-(R)-Pro-Trp-PheNH2) displayed a higher affinity than endogenous endomorphin-1, as revealed by their K(i) values (0.33 and 11.1 nM, respectively). (C) 2000 Elsevier Science Ltd.
- Cardillo, Giuliana,Gentilucci, Luca,Melchiorre, Paolo,Spampinato, Santi
-
p. 2755 - 2758
(2007/10/03)
-
- Constrained β-alanine based GpIIb/IIIa antagonists
-
The concepts of centrally constrained and peptide based fibrinogen receptor antagonists have been successfully combined into a single series of analogs which have been demonstrated to be potent inhibitors of platelet aggregation.
- Klein, Scott I.,Czekaj, Mark,Molino, Bruce F.,Valeria, Chu
-
p. 1773 - 1778
(2007/10/03)
-