Cys-Ser-Cys-Ser-Ser-Leu-Met-Asp-Lys-Glu-Cys-Val-Tyr-Phe-Cys-His-Leu-Asp-Ile-Ile-Trp-Val-Asn-Thr-Pro-Glu-Arg-Val-Val-Pro-Tyr-Gly-Leu-Gly-Ser-Pro-Ser-Arg-Ser [Disulfide Bridges: 1-15; 3-11]

Big endothelin-1 is a 39 amino acid peptide, which is synthesized and secreted by vascular smooth muscle and endothelium cells. It is produced as an inactive enzyme, and is cleaved and activated by serine and aspartic proteases and metalloproteinases. Activated form is called ET-1, which is a potent vasoconstrictor. ET-1 is also produced by the action of endothelin converting enzyme (ECE) on big-ET-1. In guinea pigs, big-ET-1 causes the release of prostanoids and thromboxanes.

Big Endothelin 39 rat has been used for charting of a standard curve in the study of the role of ET-1 in ventricular dilatation.

Precursor of Endothelin-1; vasoconstrictor activity appears to be due to its conversion to endothelin 1 by endothelin converting enzyme in the tissue.