121377-67-1 ET-(16-21) Endothelin (16-21) His-leu-asp-ile-ile-trp Histidyl-leucyl-aspartyl-isoleucyl-isoleucyl-tryptophan L-Tryptophan, N-(N-(N-(N-(N-L-histidyl-L-leucyl)-L-alpha-aspartyl)-L-isoleucyl)-L-isoleucyl)-