| Size | Price | Stock | Qty |
|---|---|---|---|
| 10mg |
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| 100mg | |||
| Other Sizes |
| Targets |
It binds to δ‑ and μ‑opioid receptors (GPCRs), activating Gi proteins to inhibit adenylyl cyclase, reduce cAMP, and modulate ion channels (K+ efflux, Ca2+ influx). This decreases neuronal excitability. Its analgesic effect is mediated mainly via μ‑receptors, while δ‑receptors contribute to mood regulation. It also modulates dopamine release. Its endogenous role is crucial for pain control.
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|---|---|
| ln Vitro |
Two kinds of opioid peptides that are present in the spinal cord's dorsal horn include dynorphin and enkephalins, which include met-enkephalin, leucine-enkephalin, and enkephalin-8. There are three primary subtypes of opioid receptors: mu, delta, and kappa. Potential endogenous ligands for delta and kappa opioid receptors are enkephalin and dynorphin, respectively. Three receptor types that resemble the delta and kappa opioid receptors seen in vertebrates have been identified by autoradiography and pharmacologically described in brain tissue (e.g., Ki=18.9 nM for leucine enkephalin). C's CHH terminal. maenas SG [1]. The mammalian brain naturally contains a pentapeptide called leucine-enkephalin, which has characteristics similar to morphine [2].
In vitro, Leu‑enkephalin displaces [³H]‑naloxone from opioid receptors with Ki values of 3.4 nM (μ) and 4.0 nM (δ) in membrane preparations. In functional GTPγS binding assays, it stimulates G protein activation with EC50 ~10 nM. In SH‑SY5Y cells expressing MOR, it inhibits forskolin‑stimulated cAMP accumulation (IC50 ~5 nM). It shows no cytotoxicity at 1 µM. |
| ln Vivo |
Cellular assays use CHO cells stably expressing MOR or DOR. Cells are pre‑treated with Leu‑enkephalin (0.1‑100 nM) for 15 min, then cAMP is measured by ELISA. Antagonists (naloxone, naltrindole) block the effect. For receptor internalisation, cells are stained with anti‑Flag antibody and imaged. These assays confirm its potent agonist activity.
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| Enzyme Assay |
Non‑cellular binding assays: membrane homogenates from rat brain or transfected cells are incubated with [³H]‑diprenorphine (1 nM) and varying Leu‑enkephalin (0.01‑1000 nM) for 1 h at 25°C, then filtered. Ki values are calculated from displacement curves. Peptidase degradation is measured by HPLC after incubation with plasma; half‑life ~2 min.
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| Animal Protocol |
In vivo, intracerebroventricular (i.c.v.) injection in mice (10‑100 µg) produces dose‑dependent analgesia in the tail‑flick test, with peak effect at 10 min and duration ~20 min. This is reversed by naloxone. It also reduces gastrointestinal transit (charcoal meal) by 40% at 50 µg i.c.v. However, intravenous administration is ineffective due to rapid degradation. Stable analogues are used in research.
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| ADME/Pharmacokinetics |
Pharmacokinetics: plasma half‑life <1 min in rodents. It is cleaved by neprilysin and aminopeptidases. Does not cross BBB. Metabolic products are excreted renally. No oral bioavailability.
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| Toxicity/Toxicokinetics |
Toxicology: at analgesic doses, no overt toxicity. High doses may cause respiratory depression and dependence, typical of opioids. It is not genotoxic. As an endogenous peptide, it is well tolerated.
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| References | |
| Additional Infomation |
Leucine enkephalin is a pentapeptide composed of L-tyrosine, glycine, L-phenylalanine, and L-leucine residues linked by peptide bonds. It is an endogenous opioid peptide found in vertebrates, including rodents, primates, and humans, produced from the breakdown of proenkephalin or dynorphin, and possesses analgesic properties. It functions as a delta-opioid receptor agonist, a muon-opioid receptor agonist, a neurotransmitter, and an analgesic, and is also a metabolite in humans and rodents. Its function is related to L-tyrosine, glycine, L-phenylalanine, and L-leucine. It is a zwitterion of leucine enkephalin. The YGGFL zwitterion has been reported in mussels (Mytilus edulis), and relevant data are available. It is one of the endogenous pentapeptides with morphine-like activity. It differs from methionine enkephalin in that its fifth amino acid is leucine. Its first four amino acid sequences are identical to the N-terminal tetrapeptide sequence of β-endorphin.
Leu‑enkephalin is a key research tool for opioid receptor studies. It is not a drug but has inspired stable analogs like leuphasyl for cosmetic use. It is used as a biomarker for stress and pain. No clinical approval exists. Its role in addiction and mood disorders continues to be investigated. |
| Molecular Formula |
C28H37N5O7
|
|---|---|
| Molecular Weight |
555.6227
|
| Exact Mass |
555.269
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| CAS # |
58822-25-6
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| PubChem CID |
461776
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| Appearance |
White to light yellow solid powder
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| Density |
1.274 g/cm3
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| Boiling Point |
998.8ºC at 760 mmHg
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| Flash Point |
557.8ºC
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| Index of Refraction |
1.586
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| LogP |
2.101
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| Hydrogen Bond Donor Count |
7
|
| Hydrogen Bond Acceptor Count |
8
|
| Rotatable Bond Count |
15
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| Heavy Atom Count |
40
|
| Complexity |
854
|
| Defined Atom Stereocenter Count |
3
|
| SMILES |
CC(C)C[C@@H](C(=O)O)NC(=O)[C@H](CC1=CC=CC=C1)NC(=O)CNC(=O)CNC(=O)[C@H](CC2=CC=C(C=C2)O)N
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| InChi Key |
URLZCHNOLZSCCA-VABKMULXSA-N
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| InChi Code |
InChI=1S/C28H37N5O7/c1-17(2)12-23(28(39)40)33-27(38)22(14-18-6-4-3-5-7-18)32-25(36)16-30-24(35)15-31-26(37)21(29)13-19-8-10-20(34)11-9-19/h3-11,17,21-23,34H,12-16,29H2,1-2H3,(H,30,35)(H,31,37)(H,32,36)(H,33,38)(H,39,40)/t21-,22-,23-/m0/s1
|
| Chemical Name |
(2S)-2-[[(2S)-2-[[2-[[2-[[(2S)-2-amino-3-(4-hydroxyphenyl)propanoyl]amino]acetyl]amino]acetyl]amino]-3-phenylpropanoyl]amino]-4-methylpentanoic acid
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| HS Tariff Code |
2934.99.9001
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| Storage |
Powder -20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month Note: Please store this product in a sealed and protected environment, avoid exposure to moisture. |
| Shipping Condition |
Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)
|
| Solubility (In Vitro) |
DMSO : ≥ 150 mg/mL (~269.97 mM)
H2O : ~100 mg/mL (~179.98 mM) |
|---|---|
| Solubility (In Vivo) |
Solubility in Formulation 1: 6.67 mg/mL (12.00 mM) in PBS (add these co-solvents sequentially from left to right, and one by one), clear solution; with sonication.
(Please use freshly prepared in vivo formulations for optimal results.) |
| Preparing Stock Solutions | 1 mg | 5 mg | 10 mg | |
| 1 mM | 1.7998 mL | 8.9990 mL | 17.9979 mL | |
| 5 mM | 0.3600 mL | 1.7998 mL | 3.5996 mL | |
| 10 mM | 0.1800 mL | 0.8999 mL | 1.7998 mL |
*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.
Calculation results
Working concentration： mg/mL；
Method for preparing DMSO stock solution： mg drug pre-dissolved in μL DMSO (stock solution concentration mg/mL). Please contact us first if the concentration exceeds the DMSO solubility of the batch of drug.
Method for preparing in vivo formulation:：Take μL DMSO stock solution, next add μL PEG300, mix and clarify, next addμL Tween 80, mix and clarify, next add μL ddH2O，mix and clarify.
(1) Please be sure that the solution is clear before the addition of next solvent. Dissolution methods like vortex, ultrasound or warming and heat may be used to aid dissolving.
(2) Be sure to add the solvent(s) in order.
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