1,2-Dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) is a metabolite of Escherichia coli with a structure containing 18:1 fatty acids at the sn-1 and sn-2 positions. It is used as an emulsifier in order to facilitate transmembrane translocation of DNA-liposome complexes. It is coupled with cationic phospholipids using to enhance the efficiency of DNA transfection studies as a method of non-viral gene delivery. In addition, it forms heteroliposomes with N-[1-(2,3-dioleoyloxy)propyl]-N,N,N-trimethylammonium sulphate (DOTAP), which is used as a delivery vehicle for pharmacotherapeutic agents.