2-Ala-cysteamine(5)-enkephalin 99043-51-3 AC-Enkephalin Enkephalin, ala(2)-cysteamine(5)- Enkephalin, alanine(2)-cysteamine(5)- L-Phenylalaninamide, L-tyrosyl-D-alanylglycyl-N-(2-mercaptoethyl)-