| Size | Price | Stock | Qty |
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| 1mg |
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| 5mg |
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| 10mg |
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| Other Sizes |
| Targets |
N-terminally acetylated Endomorphin-1 targets the micro-opioid receptor (MOR), a G protein-coupled receptor (GPCR) that is the primary target of endogenous endorphins and clinically used opioid analgesics (e.g., morphine). Endomorphin-1 (Tyr-Pro-Trp-Phe-NH2) is one of the most selective endogenous MOR agonists known. Acetylation of the N-terminal amino group (the tyrosine residue) is a common post-translational modification that can dramatically affect receptor binding and activation. The N-terminal Tyr is critical for opioid receptor recognition and signaling. Acetylation may reduce or abolish binding affinity, convert the peptide from an agonist to an antagonist, or affect its selectivity profile. This modified peptide is used to investigate the contribution of the free N-terminal amine to MOR engagement.
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| ln Vitro |
The in vitro activity of N-terminally acetylated Endomorphin-1 is expected to be substantially reduced compared to the parent Endomorphin-1. Endomorphin-1 is a high-affinity MOR agonist with a Ki of approximately 0.4-3 nM for MOR and a Ki of >40-1000 nM for the delta-opioid receptor (DOR) and kappa-opioid receptor (KOR), demonstrating high selectivity (>100-fold). In functional assays (e.g., [3⁵S]GTPgammaS binding), Endomorphin-1 stimulates G protein activation with an EC50 of ∼2-10 nM. Acetylation of the N-terminal Tyr is known to decrease binding affinity for the micro-opioid receptor by as much as 50-1000-fold, depending on the specific modification. The acetylated analog may act as a weak partial agonist or antagonist. The compound can be used to assess whether the free NH3+ group of Tyr1 is essential for high-affinity binding.
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| ln Vivo |
A cell-free [3⁵S]GTPgammaS binding assay is used to measure micro-opioid receptor activation. Membranes from CHO cells expressing the human micro-opioid receptor (CHOhMOR) are prepared. The assay buffer contains 50 mM Tris-HCl (pH 7.4), 5 mM MgCl2, 100 mM NaCl, 1 mM DTT, and 0.1% BSA. Membranes (10-20 microg/well) are incubated with 0.1 nM [3⁵S]GTPgammaS, 10 microM GDP, and varying concentrations of N-terminally acetylated Endomorphin-1 (0.01-1000 nM) for 60 minutes at 25degC. Non-specific binding is determined with 10 microM unlabeled GTPgammaS. The reaction is terminated by rapid filtration through GF/B filters, followed by three washes with ice-cold wash buffer. Filters are dried and counted. The EC50 for stimulation of [3⁵S]GTPgammaS binding is calculated. The parent Endomorphin-1 is used as a positive control. The acetylated analog should produce a rightward shift in the concentration-response curve or a reduced maximal response (partial agonism). The compound's pEC50 (or pIC50 if antagonism is observed) is determined.
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| Enzyme Assay |
For receptor binding studies, competition binding assays are performed using the same membranes. Membranes (10-20 microg/well) are incubated with 0.5-1 nM [3H]-DAMGO (a selective MOR agonist) and varying concentrations of unlabeled N-terminally acetylated Endomorphin-1 (0.1 nM-10 microM) in binding buffer for 60-90 minutes at 25degC. Non-specific binding is determined with 10 microM naloxone. Bound radioligand is separated by rapid filtration, and Ki values are calculated using the Cheng-Prusoff equation. The acetylated analog is expected to have a Ki in the micromolar range (vs. 0.4-3 nM for the parent). Functional antagonism can be assessed by measuring inhibition of a standard MOR agonist (e.g., DAMGO or Endomorphin-1)-induced [3⁵S]GTPgammaS binding. This modified peptide is a useful tool for SAR studies.
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| Cell Assay |
For cellular assays, CHO or HEK293 cells stably expressing the micro-opioid receptor are used. For cAMP inhibition assays (a functional readout of MOR activation), cells are seeded in 96-well plates and pre-incubated with 0.5 mM IBMX (phosphodiesterase inhibitor) for 10 minutes. Cells are then treated with N-terminally acetylated Endomorphin-1 (0.1-10,000 nM) for 10 minutes, followed by forskolin (1-5 microM) for 15-30 minutes. Forskolin-stimulated cAMP is measured using a competitive ELISA or HTRF assay kit. The EC50 for inhibition of cAMP accumulation is calculated. For antagonist assays, cells are pre-incubated with the acetylated analog (0.1-10 microM) for 10 minutes, then stimulated with a sub-maximal concentration of DAMGO (e.g., 10 nM) and forskolin. The ability of the analog to block DAMGO-induced cAMP inhibition is measured. The IC50 for antagonism is calculated. For calcium mobilization assays (if the cells also co-express a chimeric G protein), cells are loaded with Fluo-4 AM, and the analog is added as described previously. However, for MOR, the primary readout is cAMP inhibition, not calcium.
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| ADME/Pharmacokinetics |
The lyophilized powder should be stored at -20degC (up to 3 years) in a sealed container, protected from moisture. For solution storage, stock solutions in DMSO (1-10 mM) should be stored at -80degC for up to 6 months and at -20degC for up to 1 month. The compound is soluble in DMSO (10-20 mg/mL). For in vitro assays, working solutions are diluted in assay buffer (containing 0.1% BSA to prevent non-specific binding). The TFA salt form (which is standard for many peptides) is not explicitly specified for this product, but the compound is likely supplied as a TFA salt or acetate salt. The C-terminal amide is present (not a free acid). This product is for research use only.
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| Toxicity/Toxicokinetics |
This product is for research use only and is not for human therapeutic use. No specific toxicity data is available for this modified peptide. Endomorphin-1 analogs are generally well-tolerated in cell culture at concentrations up to 10 microM. The TFA counterion (if present) may be cytotoxic at high concentrations (>0.1%), but this is not a concern at the working dilutions used in opioid receptor assays (final TFA concentration <<0.01%). Standard laboratory safety practices (gloves, lab coat, safety glasses) should be followed. Avoid inhalation of powder. The compound is not an FDA-approved drug. It is intended for research purposes only.
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| Additional Infomation |
Endomorphin-1 (Tyr-Pro-Trp-Phe-NH2) and Endomorphin-2 (Tyr-Pro-Phe-Phe-NH2) are endogenous opioid peptides discovered in 1997. They are the most selective endogenous agonists for the micro-opioid receptor. The N-terminal tyrosine residue is critical for opioid receptor binding, and the free NH3+ group forms a key electrostatic interaction with Asp147 in the third transmembrane domain of MOR. Acetylation of this group reduces or abolishes binding, making it a useful negative control in studies of endomorphin signaling. The compound is also referred to as Ac-Tyr-Pro-Trp-Phe-NH2. This product is not a drug and is for research use only. Supplier information must not be included.
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| Molecular Formula |
C36H40N6O6
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| Appearance |
Typically exists as solid at room temperature
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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 (e.g. under nitrogen), avoid exposure to moisture and light. |
| Shipping Condition |
Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)
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| Solubility (In Vitro) |
May dissolve in DMSO (in most cases), if not, try other solvents such as H2O, Ethanol, or DMF with a minute amount of products to avoid loss of samples
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| Solubility (In Vivo) |
Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.
Injection Formulations
Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)(e.g. IP/IV/IM/SC) *Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution. Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline) Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil) Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals). View More
Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)] Oral Formulations
Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium) Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals). View More
Oral Formulation 3: Dissolved in PEG400 (Please use freshly prepared in vivo formulations for optimal results.) |
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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