Converts big endothelin-1 to endothelin-1. Hydrolysis of the 21-Trp-|-Val-22 bond in big endothelin to form endothelin 1. Binds 1 zinc ion per subunit. Inhibited by phosphoramidon (PubMed:18992253). Activated by K49-P1-20, a twenty-residue synthetic peptide shortened from the snake B.asper myotoxin II (PubMed:26931059). Homodimer; disulfide-linked (PubMed:18992253). Interacts with PPP1R16B (By similarity). All isoforms are expressed in umbilical vein endothelial cells, polynuclear neutrophils, fibroblasts, atrium cardiomyocytes and ventricles. Isoforms A, B and C are also expressed in placenta, lung, heart, adrenal gland and phaeochromocytoma; isoforms A and C in liver, testis and small intestine; isoform B, C and D in endothelial cells and umbilical vein smooth muscle cells; isoforms C and D in saphenous vein cells, and isoform C in kidney. The disease is caused by variants affecting the gene represented in this entry. Belongs to the peptidase M13 family. Extended N-terminus.