[Directed and spontaneous disulfide bond closure using hydrogen peroxide in the synthesis of endothelins-1 and -3]

The linear precursors of endothelin 1 and endothelin 3, natural vasoactive peptides, were obtained by using the Boc- and Fmoc-schemes of solid phase peptide synthesis. The methods of directed and spontaneous formation of two disulfide bonds in the molecules of these precursors were compared and shown to give comparable results. The conditions were found that provided the selective S-S-ring closure in the methionine-containing endothelin 1 by means of hydrogen peroxide without the undesired conversion of the Met residue into the corresponding sulfoxide.