| Size | Price | Stock | Qty |
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| 5mg |
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| 10mg |
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| 50mg |
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| 100mg |
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| Other Sizes |
| Targets |
TGF-β[1]
KRFK TFA targets the TGF-beta pathway by activating latent TGF-beta (LAP-TGF-beta) through a mechanism independent of thrombospondin receptors CD47 and CD36. The KRFK sequence binds to a specific site on LAP-TGF-beta, causing a conformational change that releases active TGF-beta from its latent complex. This activation occurs without the need for proteolytic cleavage, enabling rapid TGF-beta signaling. |
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| ln Vitro |
In TSP-1-deficient bone marrow-derived dendritic cells (BMDCs), KRFK TFA (50 μM; 24 h) decreases the expression of DC maturation markers and increases TGF-β secretion [1].
In cell-free assays, KRFK TFA directly activates LAP-TGF-beta at concentrations around 2 nM. Activation can be measured in an HT-2 cell proliferation assay, where activated TGF-beta induces cell growth inhibition. The activation is completely blocked by the anti-TGF-beta monoclonal antibody 1D11, confirming specificity. The peptide does not bind to or activate TGF-beta receptors directly; it acts on the latent complex. |
| ln Vivo |
KRFK TFA (5 μg/5 μL per eye; single dosage) dramatically reduces the likelihood that TSP-1-/-mice may develop chronic ocular surface inflammation [1].
In cell-based assays, KRFK TFA (50 uM; 24 h) activates the secretion of TGF-beta and reduces the expression of DC maturation markers (e.g., CD80, CD86, MHC II) in tsp-1 deficient bone marrow-derived dendritic cells (BMDCs). The peptide also induces downstream Smad2/3 phosphorylation in various cell types. Activation is independent of TSP-1 and its receptors CD47/CD36. |
| Enzyme Assay |
To measure TGF-beta activation, LAP-TGF-beta is incubated with various concentrations (0.1-100 uM) of KRFK TFA in a cell-free system. Activated TGF-beta is quantified by ELISA using a capture antibody specific for active TGF-beta (which does not recognize latent TGF-beta). Alternatively, a bioassay using HT-2 cells (which proliferate in response to IL-2 but are growth-inhibited by TGF-beta) is performed; cell viability is measured by MTT.
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| Cell Assay |
TSP-1-deficient bone marrow-derived dendritic cells (BMDCs) are cultured from tsp-1-/- mice. Cells are treated with KRFK TFA (50 uM) for 24 hours. Supernatants are collected, and TGF-beta secretion is measured by ELISA. DC maturation markers (CD80, CD86, MHC II) are analyzed by flow cytometry. For signaling studies, cells are treated for 30-60 minutes, and Smad2/3 phosphorylation is assessed by Western blot using phospho-specific antibodies.
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| Animal Protocol |
KRFK TFA is administered topically as eye drops (5 ug/5 uL/eye, single dose) in TSP-1-/- mice, which develop chronic ocular surface inflammation. The peptide significantly prevents the development of inflammation, as assessed by clinical scoring (corneal opacity, neovascularization), histological analysis of corneal and conjunctival sections, and measurement of inflammatory cytokine levels (IL-1beta, TNF-alpha, IL-6). Efficacy is comparable to that seen with recombinant TGF-beta1.
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| ADME/Pharmacokinetics |
KRFK TFA has a molecular weight of 577.73 Da (free base) and molecular formula C27H47N9O5. It is soluble in DMSO at ≥100 mg/mL. The TFA salt form enhances peptide solubility and stability. For in vivo use, the peptide is reconstituted in sterile PBS or artificial tears (e.g., at 1 mg/mL). The peptide has a short half-life in ocular surface fluids due to rapid dilution and potential proteolysis; however, single-dose topical application provides sufficient TGF-beta activation to achieve therapeutic effects.
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| Toxicity/Toxicokinetics |
Toxicity studies for KRFK TFA have not been extensively reported. At topical doses of 5 ug/eye in mice, no signs of ocular irritation, corneal damage, or systemic toxicity were observed. The peptide is expected to have low toxicity based on its mechanism of action (activating endogenous TGF-beta) and its topical route of administration. Standard laboratory safety precautions should be followed. Not for human use.
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| References | |
| Additional Infomation |
KRFK TFA is a research peptide not approved for clinical use. Its sequence is derived from the type 1 repeats of thrombospondin-1 (TSP-1), specifically the RFK region (residues 415-417) which is critical for TGF-beta activation. The KRFK peptide serves as a tool to study TGF-beta activation mechanisms and has potential therapeutic applications for chronic ocular surface inflammation, wound healing, and immune tolerance. The TFA salt form enhances stability and solubility.
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| Molecular Formula |
C27H47N9O5.XC2HF3O2
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| Molecular Weight |
577.73 (free base)
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| Related CAS # |
KRFK;162290-78-0
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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) |
DMSO :≥ 100 mg/mL
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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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