2-Ala-O-benzyl-5-ser-enkephalin 86248-85-3 Abs-enkephalin Enkephalin, ala(2)-O-benzyl-ser(5)- Enkephalin, alanyl(2)-O-benzylserine(5)- L-Serine, O-(phenylmethyl)-N-(N-(N-(N-L-tyrosyl-D-alanyl)glycyl)-L-phenylalanyl)-