| Size | Price | Stock | Qty |
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| 1mg |
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| 5mg |
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| Other Sizes |
| Targets |
Cholecystokinin-33 free acid targets the Cholecystokinin receptor (CCK receptor), which is a G protein-coupled receptor (GPCR) involved in neuronal signaling and digestion. The C-terminal amide group is crucial for high-affinity binding and full biological activity; its removal reduces receptor binding affinity.
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| ln Vitro |
In vitro, Cholecystokinin-33 free acid has decreased biological activity compared to native CCK-33 due to the absence of the C-terminal amide group. It is used as a comparative control to study the structure-activity relationship (SAR) of CCK family peptides and the importance of C-terminal amidation.
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| ln Vivo |
Cholecystokinin-33 free acid serves as a valuable tool in both in vitro and in vivo models to investigate the functional role of C-terminal amidation. It is used as a control to assess the contribution of this post-translational modification to receptor activation, signaling pathways, and physiological relevance.
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| Enzyme Assay |
For in vitro binding assays, the affinity of Cholecystokinin-33 free acid for CCK receptors is determined using radioligand binding or surface plasmon resonance (SPR). Varying concentrations of the free acid are incubated with membrane preparations containing CCK receptors and a radiolabeled CCK ligand. The bound radioactivity is measured.
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| Cell Assay |
For cell-based assays, cells expressing CCK receptors (e.g., CHO or AR42J cells) are treated with Cholecystokinin-33 free acid or native CCK-33. Receptor activation is measured by intracellular calcium mobilization or cAMP accumulation. The reduced potency of the free acid confirms the importance of C-terminal amidation.
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| Animal Protocol |
For animal studies, Cholecystokinin-33 free acid is administered to rodents via intraperitoneal or intracerebroventricular injection. Typical endpoints include food intake, gallbladder contraction, and pancreatic secretion. It serves as a negative control compared to amidated CCK-33 to assess the role of amidation in vivo.
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| ADME/Pharmacokinetics |
As a peptide, Cholecystokinin-33 free acid has a molecular weight of 3946.43 Da. It is supplied as a lyophilized powder and should be stored at -20degC, protected from moisture and light. The free acid form has reduced metabolic stability compared to the amidated form due to increased susceptibility to carboxypeptidases.
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| Toxicity/Toxicokinetics |
Cholecystokinin-33 free acid is a research-grade peptide not for human use. It is considered non-toxic at standard research doses. Standard precautions for handling peptides (e.g., avoiding inhalation, skin contact) should be followed. No significant toxicity is expected at typical research concentrations.
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| References |
[1]. Chandra, Rashmi, and Liddle, Rodger A. Regulation of Pancreatic Secretion. Pancreapedia: Exocrine Pancreas Knowledge Base. 2020.
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| Additional Infomation |
Cholecystokinin-33 free acid is a research tool with a sequence: KAPSGRMSIVKNLQNLDPSHRISDRD-(Tyr(SO3H))-MGWMDF. The absence of C-terminal amidation reduces its potency, making it valuable for studying the functional role of this modification. It is typically supplied with a purity of ≥95% as a solid.
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| Molecular Formula |
C167H262N50O53S4
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|---|---|
| Molecular Weight |
3946.43
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| Related CAS # |
Cholecystokinin;9011-97-6
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| Appearance |
White to off-white solid powder
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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 |
| 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.) |
| Preparing Stock Solutions | 1 mg | 5 mg | 10 mg | |
| 1 mM | 0.2534 mL | 1.2670 mL | 2.5339 mL | |
| 5 mM | 0.0507 mL | 0.2534 mL | 0.5068 mL | |
| 10 mM | 0.0253 mL | 0.1267 mL | 0.2534 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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