Formula :C₃₄H₃₈N₆O₅
M.W. 610.7 
Solubility:soluble in water.
Chemcial structure:

  
     Endomorphin-1 (EM-1) should be stored at -20°C. Keep container tightly closed.Endomorphin-1 (189388-22-5) is a recently isolated endogenous peptide having potent analgesic activity and high affinity and selectivity for the mu-opioid receptor. Endomorphin-1 (189388-22-5) activates G proteins and inhibits adenylyl cyclase activity in membrane preparations from cells stably expressing the mu opioid receptor, an effect reversed by the mu receptor antagonist CTAP (D-Phe-Cys-Tyr-D-Trp-Arg-Thr-Pen-Thr-NH2) . However, Endomorphin-1 appears to have no influence on cells stably expressing the delta opioid receptor.
     Endomorphin-1 (Tyr-Pro-Trp-Phe-NH₂) and endomorphin-2 (Tyr-Pro-Phe-Phe-NH₂) are tetrapeptides with the highest known affinity and specificity for the μ opioid receptor.Endomorphin-1 is located in the nucleus of the solitary tract, the periventricular hypothalamus, and the dorsomedial hypothalamus, where it is found within histaminergic neurons and may regulate sedative and arousal behaviors.