Purity > 90% as determined by SDS-PAGE. MW: 48.5kDa. Full Length of Mature Protein: 21-427aa. C-terminal 10xHis-tagged. Homo sapiens (Human). Receptor for endothelin-1. Mediates its action by association with G proteins that activate a phosphatidylinositol-calcium second messenger system. The rank order of binding affinities for ET-A is: ET1 > ET2 >> ET3.