Preparation of C-terminal modified peptides through alcoholysis and thiolysis mediated by metal ions
C-terminal modified peptides can be used as enzyme substrates or inhibitors, act as peptide analogs with altered biological activity and serve as acyl donors in chemical or enzymatic convergent synthesis . These compounds can be obtained by the following routine: 1) stepwise peptide synthesis on polymeric resin; 2) appropriate nucleophilic attack on the peptide-resin linkage to generate the C-terminal modified protected peptide; 3) removal of the side-chain blockers; 4) purification of the crude product; 5) final chemical characterization. Since the use of conventional procedures to perform step 2 may not always furnish products of good quality with satisfactory yields, we have studied a mild procedure to produce C-terminal modified protected peptides based on mediation by metal ions of the nucleophilic attack on the peptide-resin linkage . The Kaiser Oxime Resin (KOR) has shown to be the most suitable polymeric resin and, among Ca2+, Zn2+, Co2+ and Cu2+, the first...
KeywordsTris Buffer Acyl Donor Calcium Salt Amino Acid Ester Porcine Pancreatic Lipase
We thank FAPESP for the grant to MTMM and the postgraduate scholarship to PBP, C.W. Liria for the amino acids analyses and F.M. Prado for the technical support in the mass spectrometry analyses.
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