Solution synthesis of Na+,K(+)-ATPase inhibitor-1 (SPAI-1).

SPAI-1, a 49-amino acid peptide including eight Cys residues with Na+,K(+)-ATPase inhibitory activity, was synthesized by the solution procedure. Protecting groups, including the formyl group on the Trp residue, were cleaved simultaneously by HF treatment in the presence of a sufficient amount of thiol compound. After removal of the Acm group on the Cys residue, the resulting octa SH peptide was subjected to an oxidative folding reaction in the presence or absence of redox reagents and/or denaturant.

Synthesis and structure-activity relationships of elafin, an elastase-specific inhibitor.

Elafin, an elastase-specific inhibitor isolated from human skin, and its related peptides were synthesized by the solution procedure, and their inhibitory activities were measured against various enzymes. During the oxidative folding reactions of the reduced peptides, the ratio of the active product to the inactive product was varied by changing the concentration of guanidine HCl and the amount of redox reagents. The disulfide structures of fully active synthetic elafin and the inactive product were determined by amino acid analysis, gas-phase sequencing and mass spectrometry of their proteolytic fragments.

Solution conformation of endothelin determined by means of 1H-NMR spectroscopy and distance geometry calculations.

The structure of endothelin-1 (ET-1), an endothelial cell-derived peptide with vasoconstricting activity, was determined in an aqueous solution by means of a combination of NMR and distance geometry calculations. The resulting structure is characterized by an alpha-helical conformation in the sequence region, Lys9-Cys15. Furthermore, an extended structure and a turn structure exist in the Cys1-Ser4 and Ser5-Asp8 regions respectively, and no preferred conformation was found for the C-terminal part of the peptide which was not uniquely constrained by the NMR data.

The biological activity of endothelin-1 analogues in three different assay systems.

Endothelin (ET) is a vasoconstrictor peptide with 21-amino acid residues. In this study, we determined the relative potencies of ET-1 analogues to investigate the essential moiety of ET-1 for expression of its biological effect. We synthesized ET-1 analogues with the substitution of one amino acid at positions 2-18 and 21.