2-Cys-5-cysnh2-enkephalin 70768-44-4 CCAE D-Cysteinamide, L-tyrosyl-D-cysteinylglycyl-L-phenylalanyl-, cyclic (2-5)-disulfide Enkephalin, cys(2)-cysnh2(5)- Enkephalin, cysteinyl(2)-cysteinamide(5)-