Endomorphin-2 (EM-2) (amino acid sequence Tyr-Pro-Phe-Phe-NH2) is an endogenous opioid peptide and one of the two endomorphins. It is a high affinity, highly selective agonist of the μ-opioid receptor, and along with endomorphin-1 (EM-1), has been proposed to be the actual endogenous ligand of this receptor (that is, rather than the endorphins). Like EM-1, EM-2 produces analgesia in animals, but whereas EM-1 is more prevalent in the brain, EM-2 is more prevalent in the spinal cord. In addition, the action of EM-2 differs from that of EM-1 somewhat, because EM-2 additionally induces the release of dynorphin A and [Met]enkephalin in the spinal cord and brain by an unknown mechanism, which in turn go on to activate the κ- and δ-opioid receptors, respectively, and a portion of the analgesic effects of EM-2 is dependent on this action. Moreover, while EM-1 produces conditioned place preference, a measure of drug reward, EM-2 produces conditioned place aversion, an effect which is dynorphin A-dependent. Similarly to the case of EM-1, the gene encoding for EM-2 has not yet been identified.

CAS：141801-26-5
中文别名：TYR-PRO-PHE-PHE-NH2;
英文别名：H-Tyr-Pro-Phe-Phe-NH2;(2S)-1-[(2S)-2-amino-3-(4-hydroxyphenyl)propanoyl]-N-[(2S)-1-[[(2S)-1-amino-1-oxo-3-phenylpropan-2-yl]amino]-1-oxo-3-phenylpropan-2-yl]pyrrolidine-2-carboxamide;
分子式：C32H37N5O5
分子量：571.667
精确质量：571.279
Psa：167.85
Logp：3.3136

UNII：3PH5M0466G

密度：1.292g/cm3
沸点：972.4ºC at 760mmHg
闪点：541.9ºC
折射率：1.632
储存条件：-20ºC
蒸汽压：0mmHg at 25°C