• USA Home
  • M6638 - [Met5]Enkephalin acetate salt hydrate

M6638 Sigma-Aldrich

[Met5]Enkephalin acetate salt hydrate

≥95.0% (HPLC), powder

Synonym: Enkephalin M, [5-Methionine]Enkephalin

  • CAS Number 82362-17-2

  • Empirical Formula (Hill Notation) C27H35N5O7S · xC2H4O2 · yH2O

  • Molecular Weight 573.66 (anhydrous free base basis)

  •  Beilstein/REAXYS Number 3042295

  •  MDL number MFCD03788202

  •  PubChem Substance ID 24897102

  •  NACRES NA.32



Related Categories Cell Biology, Cell Signaling and Neuroscience, Enkephalins, Neuropeptides, Opioid Peptides,
Quality Level   200
assay   ≥95.0% (HPLC)
form   powder
composition   acetate, 2.5-20%
color   white
storage temp.   −20°C
SMILES string   O=C([C@H](CC1=CC=CC=C1)NC(CNC(CNC([C@@H](N)CC(C=C2)=CC=C2O)=O)=O)=O)N[C@@H](CCSC)C(O)=O.CC(O)=O.[H]O[H]
InChI   1S/C27H35N5O7S.C2H4O2.H2O/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;1-2(3)4;/h2-10,20-22,33H,11-16,28H2,1H3,(H,29,34)(H,30,36)(H,31,35)(H,32,37)(H,38,39);1H3,(H,3,4);1H2/t20-,21-,22-;;/m0../s1
Gene Information   human ... OPRD1(4985), OPRM1(4988)
mouse ... OPRD1(18386), OPRM1(18390)
rat ... OPRD1(24613), OPRM1(25601)


Amino Acid Sequence


General description

[Met5] Enkephalin (ME) is an opioid pentapeptide, which acts as a neurotransmitter or neuromodulator in the central nervous system. [Met5] Enkephalin is activated on interaction with three main subtypes of receptors including μand δ opioid receptors mediating classic opioid effects of met-Enk and ζ -receptors mediating non-opioid actions of the peptide, i.e. retardation of cell growth. [Met5] Enkephalin is derived from precursor peptide pro-methionine-enkephalin in vitro consisting of H-Tyr-Gly-Gly-Phe-Met-Arg-OH amino acid sequence. The peptide activity is observed in the central nervous, neuroendocrine and immune systems.


[Met5] Enkephalin acetate salt hydrate has been used to study the effect of mutations in opioid growth factor receptor on growth of human cancer cell line.

Biochem/physiol Actions

Met-enkephalin is endogenous opioid neurotransmitter/neuromodulator with agonist activity at μ and δ opioid receptors. Enhancement of immune system function is mediated through met-enkephalin receptors on leukocytes. Met-enkephalin also functions as a growth factor on many cell types at a receptor that is distinct from the neuronal opioid receptors.

Opioid peptides play a crucial role in various physiological process such as pain mediation, opiate dependence and euphoria and members of this class contain aromatic residues in positions 1 and 4. [Met5] Enkephalin acts as a cytokine and is implicated in improving immune response in patients with cancer or AIDS. [Met5] Enkephalin boosts immune functions at low concentration and suppress at high concentration. ME is associated with glucose homeostasis. Increased concentration of ME is observed in plasma of type I diabetic patients.

Safety & Documentation

Safety Information

Personal Protective Equipment 
NONH for all modes of transport
WGK Germany 
Flash Point(F) 
Not applicable
Flash Point(C) 
Not applicable


Certificate of Analysis (COA)

Please Enter a Lot Number

Certificate of Origin (COO)

Please Enter a Lot Number
Protocols & Articles
Peer-Reviewed Papers


Related Products

related product

Product #


Add to Cart

06693 Timestrip Plus -20 °C

Technical Service:

Our team of scientists has experience in all areas of research including Life Science, Material Science, Chemical Synthesis, Chromatography, Analytical and many others.

Bulk Ordering & Pricing:

Need larger quantities for your development, manufacturing or research applications?