The synthesis of N-acyl- -mercaptoalanine derivatives

Synthesis of Hybrid Tripeptide Peptidomimetics Containing Dehydroamino Acid and Aminophosphonic Acid in the Chain and Evaluation of Their Activity toward Cathepsin C

Synthesis of a new group of hybrid phosphonodehydropeptides composed of glycyl-(Z)-dehydrophenylalanine and structurally variable aminophosphonates alongside with investigations of their activity towards cathepsin C are presented. Obtained results suggest that the introduction of (Z)-dehydrophenylalanine residue into the short phosphonopeptide chain does induce the ordered conformation. Investigated peptides appeared to act as weak or moderate inhibitors of cathepsin C.

Pentapeptides containing two dehydrophenylalanine residues--synthesis, structural studies and evaluation of their activity towards cathepsin C

Synthesis, structural and biological studies of pentapeptides containing two DeltaPhe residues (Z and E isomers) in position 2 and 4 in peptide chain were performed. All the investigated peptides adopted bent conformation and majority of them could exist as two different conformers in solution. Only pentapeptides, containing free N-termini appeared to act as weak inhibitors of cathepsin C with the slow-binding, competitive mechanism of inhibition, free acids being bound slightly better than their methyl esters. Results of molecular modeling suggested significant difference between peptides, depending of the type of amino acid residue in position 5 in peptide chain. Dehydropeptides containing Gly residue in this position may act as competitive slow-reacting substrates and therefore exhibit inhibitory-like properties.

Norcystine, a new tool for the study of the structure-activity relationship of peptides

[reaction: see text] Norcysteine (Ncy) is an unnatural amino acid possessing an electronegative sulfur atom directly attached to the alpha-carbon atom. We describe the synthesis of Boc-D,L-Ncy(Mob)-OH, the resolution of its methyl ester, and the introduction of both D- and L-Ncy in GnRH analogues.

Synthesis of tetrapeptide p-nitrophenylanilides containing dehydroalanine and dehydrophenylalanine and their influence on cathepsin C activity

Three dehydrotetrapeptides of rationally varying structure were prepared and tested as affectors of cathepsin C. These compounds appeared to be substrates of the enzyme, being equipotent with their classical counterparts. Thus, replacement of amino acid in a short peptide by corresponding dehydroamino acid does not prevent cathepsin C in recognizing dehydropeptide as its substrate.