Met-enkephalin

Met-enkephalin

Names
IUPAC name (2S)-2-[[(2S)-2-[[2-[[2-[[(2S)-2-Smino-3-(4-hydroxyphenyl)propanoyl]amino]acetyl]amino]acetyl]amino]-3-phenylpropanoyl]amino]-4-methylsulfanylbutanoic acid
Other names [Methionine]enkephalin; L-Tyrosylglycylglycyl-L-phenylalanyl-L-methionine
Identifiers
CAS Number	58569-55-4 Y
3D model (Jmol)	Interactive image Interactive image
ChemSpider	391597 Y
ECHA InfoCard	100.055.741
EC Number	261-335-8
IUPHAR/BPS	1614
KEGG	C11684 N
MeSH	Enkephalin,+Methionine
PubChem CID	443363
InChI InChI=1S/C27H35N5O7S/c1-40-12-11-21(27(38)39)32-26(37)22(14-17-5-3-2-4-6-17)31-24(35)16-29-23(34)15-30-25(36)20(28)13-18-7-9-19(33)10-8-18/h2-10,20-22,33H,11-16,28H2,1H3,(H,29,34)(H,30,36)(H,31,35)(H,32,37)(H,38,39) N Key: YFGBQHOOROIVKG-UHFFFAOYSA-N N
SMILES CSCCC(NC(=O)C(Cc1ccccc1)NC(=O)CNC(=O)CNC(=O)C(N)Cc1ccc(O)cc1)C(O)=O CSCCC(NC(=O)C(CC1=CC=CC=C1)NC(=O)CNC(=O)CNC(=O)C(N)CC1=CC=C(O)C=C1)C(O)=O
Properties
Chemical formula	C27H35N5O7S
Molar mass	573.67 g·mol−1
log P	0.607
Acidity (pKa)	3.234
Basicity (pKb)	10.763
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YN ?)
Infobox references

Met-enkephalin, also known as metenkefalin (INN), sometimes referred to as opioid growth factor (OGF), is a naturally occurring, endogenous opioid peptide that has opioid effects of a relatively short duration. It is one of the two forms of enkephalin, the other being leu-enkephalin. The enkephalins are considered to be the primary endogenous ligands of the δ-opioid receptor, due to their high potency and selectivity for the site over the other endogenous opioids.

Met-enkephalin was discovered and characterized by John Hughes, Hans Kosterlitz, et al. in 1975 after a search for endogenous ligands of the opioid receptors.

Met-enkephalin is a pentapeptide with the amino acid sequence tyr-gly-gly-phe-met. The tyrosine residue at position 1 is thought to be analogous to the 3-hydroxyl group on morphine.

Met-enkephalin is found mainly in the adrenal medulla and throughout the central nervous system (CNS), including in the striatum, cerebral cortex, olfactory tubercle, hippocampus, septum, thalamus, and periaqueductal gray, as well as the dorsal horn of the spinal cord. It is also present in the periphery, notably in some primary afferent fibers that innervate the pelvic viscera.