Studies on the disulfide bridges of sarafotoxins. Chemical synthesis of sarafotoxin S6B and its homologue with different disulfide bridges.

Sarafotoxin S6b, a strong vasocontractile peptide with 21 amino acid residues containing two sets of disulfide bridges, was chemically synthesized. The retention time on a reversed-phase HPLC, lethal and vasocontractile activities of natural sarafotoxin S6b agree with those of the synthetic [Cys1-15, Cys3-11]-sarafotoxin S6b. The combination of the disulfide bridges of sarafotoxin S6b is the same as that of endothelin-1, a mammalian vasocontractile peptide, which shows a high degree of sequence homology and shares several common pharmacological properties with sarafotoxins.