| 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 |
Kallikrein[1]
KKI-5 TFA targets tissue kallikrein (also known as kallikrein 1), a serine protease that cleaves kininogen to release the vasoactive peptide kallidin (lysyl-bradykinin). The KKI-5 peptide encompasses the aa388-389 kallikrein proteolytic site in kininogen-1, and thus acts as a competitive inhibitor, binding to the active site of kallikrein and preventing the cleavage of natural substrates such as kininogen. |
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| ln Vitro |
The aa386-391 of bovine kininogen-1, which includes the aa388-389 kallikrein proteolytic site, is equivalent to the KKI-5 Peptide. Since the synthetic KKI-5 can reduce the invasion of breast cancer cells, its function in cancer cell invasion and metastasis is being studied[1].
In cell-free assays, KKI-5 TFA inhibits the enzymatic activity of purified tissue kallikrein. The inhibition can be measured using a fluorogenic peptide substrate (e.g., Z-Phe-Arg-AMC). Kallikrein is incubated with the substrate and varying concentrations (0.1-100 uM) of KKI-5 TFA; the decrease in fluorescence (Ex 360/Em 460 nm) indicates inhibition. The IC50 for kallikrein inhibition is typically in the low micromolar range. KKI-5 may also inhibit plasmin. |
| ln Vivo |
In breast cancer cell lines (e.g., MDA-MB-231, MCF-7), KKI-5 TFA (10-100 uM) reduces cancer cell invasion as measured by Matrigel transwell assays. Cells are seeded in the upper chamber with KKI-5 TFA and allowed to invade through Matrigel towards a chemoattractant (e.g., 10% FBS or growth factors). The peptide attenuates invasion without significantly affecting cell viability at these concentrations, indicating its effect on motility rather than general cytotoxicity.
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| Enzyme Assay |
In a cell-free fluorometric assay, purified human tissue kallikrein (kallikrein 1) is incubated with the fluorogenic substrate Z-Phe-Arg-AMC (50 uM) in Tris-HCl buffer (pH 8.0) containing 0.1% BSA. Varying concentrations (0.1-100 uM) of KKI-5 TFA are added, and the reaction is incubated at 37degC for 30-60 minutes. Fluorescence is measured (Ex 360 nm, Em 460 nm). The IC50 is calculated from dose-response curves. Controls include no inhibitor and a known kallikrein inhibitor (e.g., aprotinin).
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| Cell Assay |
MDA-MB-231 breast cancer cells are cultured in DMEM with 10% FBS. For invasion assays, transwell inserts (8 um pore size) are coated with 100 uL of 1 mg/mL Matrigel and allowed to solidify. Cells (5×10⁴ in 200 uL serum-free medium) are seeded in the upper chamber with KKI-5 TFA (0-100 uM). The lower chamber contains 600 uL of medium with 10% FBS as a chemoattractant. After 24-48 hours, non-invaded cells on the upper membrane surface are removed by cotton swab, and invaded cells on the lower surface are fixed, stained with crystal violet, and counted under a microscope.
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| Animal Protocol |
KKI-5 TFA can be evaluated in mouse models of breast cancer metastasis. For example, MDA-MB-231-luc2 cells are injected intravenously via the tail vein to establish lung metastasis models. Mice are treated with KKI-5 TFA (e.g., 10-50 mg/kg) via intraperitoneal or intravenous injection daily or every other day for 3-4 weeks. Tumor metastasis burden is monitored by bioluminescence imaging (for luciferase-labeled cells) or by ex vivo lung tissue analysis (e.g., counting metastatic nodules). The peptide is expected to reduce metastatic colonization.
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| ADME/Pharmacokinetics |
KKI-5 TFA is a synthetic peptide with a molecular weight of 887.90 Da and molecular formula C37H56N11O11 (plus TFA). The TFA salt enhances solubility. The peptide has a short half-life (minutes) due to rapid proteolytic degradation and renal clearance, requiring frequent dosing or continuous infusion for in vivo studies. It can be formulated in sterile water or PBS for injection. For long-term studies, conjugation to PEG or formulation in slow-release microparticles may be beneficial.
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| Toxicity/Toxicokinetics |
KKI-5 TFA is generally well-tolerated at research doses (10-50 mg/kg in mice). No significant systemic toxicity or organ damage has been reported. Since kallikrein inhibition may affect blood pressure regulation, careful monitoring of hemodynamic parameters is advised in some study designs. Standard laboratory safety precautions (gloves, lab coat) should be followed. The compound is for research use only and not for human therapeutic use.
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| References | |
| Additional Infomation |
KKI-5 TFA is a research-use-only peptide inhibitor of tissue kallikrein. The sequence Ac-PFRSVQ-NH2 corresponds to the kallikrein proteolytic site in bovine kininogen-1 (residues 386-391). It was originally described as a novel serine protease inhibitor that inhibits both kallikrein and plasmin, with anticancer activity against breast cancer cell invasion and metastasis. KKI-5 TFA may also have potential for treating angioedema. Not approved for clinical use.
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| Molecular Formula |
C37H56F3N11O11
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| Molecular Weight |
887.90
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| Related CAS # |
KKI-5;97145-43-2
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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 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)
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| Solubility (In Vitro) |
H2O :~9.09 mg/mL (~10.24 mM)
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| Solubility (In Vivo) |
Solubility in Formulation 1: 12.5 mg/mL (14.08 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 | 1.1263 mL | 5.6313 mL | 11.2625 mL | |
| 5 mM | 0.2253 mL | 1.1263 mL | 2.2525 mL | |
| 10 mM | 0.1126 mL | 0.5631 mL | 1.1263 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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