E1 is one of two subunits of the envelope glycoprotein found in the hepatitis C virus. The other subunit is E2.This protein is a type 1 transmembrane protein with a highly glycosylated N-terminal ectodomain and a C-terminal hydrophobic anchor. After being synthesized the E1 glycoproteins associates with the E2 glycoprotein as a noncovalent heterodimer.