Sarafotoxin 6c (S6c) is a specific agonist for the endothelin-B- (ETB) receptor, being largely used as a standard compound in pharmacological studies related to ETB-receptors. We have developed an improved peptide synthesis procedure. Using the Fmoc chemistry methodology and an appropriate orthogonal protection scheme, we obtained a crude peptide with a major component identified as [Cys(Acm)1,15]S6c. A silver salt (AgBF4) treatment of this crude material completely removed the Acm moieties without the appearance of any major side-products. The free peptide was cyclized using a Fe3+/Fe2+ oxidizing method. Besides the formation of the bridges, no other modification was observed. Thus, the peptide purification was facilitated and an excellent yield of pure sarafotoxin was obtained. The material was characterized by analytical reverse phase-high performance liquid chromatography (RP-HPLC) and matrix assisted laser desorption ionizationtime of flight (MALDI-TOF) mass spectrometry. Pharmacological properties of the peptide were evaluated in an ETB preparation (guinea pig lung parenchyma strips) and were identical to those of an S6c standard.
Address correspondence and reprint requests to Dr Alain Fournier, Centre de recherche en santé humaine, INRS/Institut Armand-Frappier, Université du Québec, 245 boulevard Hymus, Pointe-Claire, QC, Canada H9R 1G6. E-mail: [email protected]
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