Names | |
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IUPAC name
L-Tyrosyl-L-prolyl-L-phenylalanyl-L-phenylalaninamide
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Identifiers | |
3D model (
JSmol)
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ChemSpider | |
PubChem
CID
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UNII | |
CompTox Dashboard (
EPA)
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Properties | |
C32H37N5O5 | |
Molar mass | 571.667 g/mol |
Except where otherwise noted, data are given for materials in their
standard state (at 25 °C [77 °F], 100 kPa).
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Endomorphin-2 (EM-2) is an endogenous opioid peptide and one of the two endomorphins. [1] It has the amino acid sequence Tyr-Pro-Phe-Phe-NH2. 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). [1] [2] [3] [4] 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. [1] 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. [5] [6] 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. [6] Similarly to the case of EM-1, the gene encoding for EM-2 has not yet been identified. [4] [7]