It is demonstrated that carboxypeptidase Y from Saccharomyces cerevisiae can catalyze the formation of peptide bonds using N-acylamino acid esters as substrates and free amino acids or amino acid amides as nucleophiles, The coupling yields observed with free amino acids were max. 60 % for alanine and lysine and they depended strongly on the reaction parameters; viz. pH, temperature and concentr...

In previous investigations, we have examined the effect of OmpA signal peptide mutations on the secretion of the two heterologous proteins TEM beta-lactamase and nuclease A. During these studies, we observed that a given signal peptide mutation could affect differentially the processing of precursor OmpA-nuclease or precursor OmpA-lactamase. This observation led us to further investigate the in...

The use of polymeric supports in solid-phase peptide synthesis has allowed for the facile, rapid synthesis of short peptides in a one bead/one sequence manner. This approach allows for screening peptide libraries for binding and catalytic activities. Once hits are found, the sequence of the active protein can be determined via mass spectrometry. However, problems arise when trying to create lar...

The combination of solid phase peptide synthesis and endo-β-N-acetylglucosaminidase (ENGase) catalysed glycosylation is a powerful convergent synthetic method allowing access to glycopeptides bearing full-length N-glycan structures. Mannose-terminated N-glycan oligosaccharides, produced by either total or semi-synthesis, were converted into oxazoline donor substrates. A peptide from the human c...

The first total synthesis of Rolloamide B, a cyclic proline-enriched heptapeptide, is reported. This work features solution phase benzotriazole-mediated peptide synthesis ligating native amino acids.

Decorsin is a 39-residue polypeptide chain, crosslinked by three disulfide bridges, that strongly inhibits platelet aggregation. We report the chemical synthesis and characterization of analogs of decorsin with the aim of investigating the role of proline residues in protein structure, stability and biological activity. Decorsin analogs have been synthesized in which one (P23A and P24A decorsin...

Photogenerated acid (PGA) was used as the acid to remove the protection group from amino acids or peptide oligomers. Comparative study of the deprotection using a PGA, trisarylsulfonium antimonyhexafluoride (SSb), and trifluoroacetic acid (TFA) was performed on glass microscope slides. The results showed that PGA can replace TFA in the deprotection step of oligopeptide synthesis with comparable...