| Size | Price | Stock | Qty |
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| 10mg |
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| 25mg |
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| 50mg |
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| 100mg |
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| Other Sizes |
| Targets |
Cleavable Linker Protease Cleavable Linker
Phe-Lys(Fmoc)-PAB does not have a specific biological target itself but serves as a cleavable linker for bioconjugation. The peptide sequence Phe-Lys is recognized by cathepsin B and other proteases that are overexpressed in tumor cells, enabling selective drug release. As an ADC linker, it enables the conjugation of cytotoxic payloads to antibodies, facilitating selective delivery of drugs to cancer cells. The Fmoc protecting group allows for controlled peptide synthesis. |
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| ln Vitro |
In vitro activity of Phe-Lys(Fmoc)-PAB is assessed by its ability to form stable conjugates with antibodies and its selective cleavage by cathepsin B. The efficiency of conjugation to antibodies is evaluated by SDS-PAGE, mass spectrometry, and HPLC. The cleavable nature of the peptide linker is confirmed by incubation with cathepsin B or other relevant proteases, followed by analysis of conjugate stability and drug release by HPLC or LC-MS.
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| ln Vivo |
In vivo studies for Phe-Lys(Fmoc)-PAB are typically conducted as part of complete ADC development. The ADC is evaluated in mouse xenograft models bearing target-positive tumors. Efficacy is assessed by tumor growth inhibition, and pharmacokinetic studies evaluate the stability of the linker in circulation. The peptide-based cleavable linker is designed to enable selective drug release in the tumor microenvironment where cathepsin B is overexpressed.
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| Enzyme Assay |
For conjugation assays, Phe-Lys(Fmoc)-PAB is activated and conjugated to antibodies or targeting proteins. The reaction is typically conducted in the presence of coupling reagents. The extent of conjugation is monitored by SDS-PAGE or MALDI-TOF mass spectrometry. For cleavage studies, the conjugate is incubated with cathepsin B at 37°C, and the release of payload is analyzed by HPLC or LC-MS. The stability of the conjugate in plasma is assessed by incubation in mouse or human plasma at 37°C.
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| Cell Assay |
For cellular studies, target-positive cancer cell lines are cultured in appropriate media and treated with Phe-Lys(Fmoc)-PAB-containing ADC conjugates at various concentrations for 24-72 hours. Cell viability is assessed using MTT or CellTiter-Glo assays, and IC50 values are calculated. Cell binding is evaluated by flow cytometry using fluorescently labeled conjugates, and internalization is assessed using confocal microscopy. For protease-dependent activity, cells are co-treated with cathepsin inhibitors.
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| Animal Protocol |
For in vivo efficacy studies, immunodeficient mice bearing target-positive tumor xenografts are administered the complete ADC via intravenous injection. Dosing typically involves multiple injections at 1-2 week intervals. Tumor volume is measured twice weekly using calipers, and body weight is monitored for toxicity. At study termination, tumors and major organs are collected for histopathological analysis and drug concentration measurement.
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| ADME/Pharmacokinetics |
Pharmacokinetic properties of Phe-Lys(Fmoc)-PAB are characterized as part of the complete ADC. The peptide-based linker provides a cleavable mechanism for drug release in the tumor microenvironment. Detailed PK parameters such as half-life, clearance, and volume of distribution depend on the specific antibody and payload used in the conjugate. The compound is typically stored at -20°C.
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| Toxicity/Toxicokinetics |
Phe-Lys(Fmoc)-PAB is a chemical reagent intended for research use only and is not approved for human therapeutic use. As a cleavable ADC linker, it enables selective drug release in the tumor microenvironment through cleavage by cathepsin B. Standard laboratory safety precautions should be followed when handling this compound. Storage at -20°C is recommended.
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| References |
[1]. Abu Ajaj K, et al. Development of protein-binding bifunctional linkers for a new generation of dual-actingprodrugs. Bioconjug Chem. 2009 Feb;20(2):390-6.
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| Additional Infomation |
Phe-Lys(Fmoc)-PAB is a cleavable peptide-based ADC linker consisting of phenylalanine-lysine with Fmoc protection and a PAB self-immolative spacer. The peptide sequence enables cleavage by cathepsin B in the tumor microenvironment. The compound is used in ADC synthesis for cancer research. It is for research use only and has not been approved for clinical applications.
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| Molecular Formula |
C37H40N4O5
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|---|---|
| Molecular Weight |
620.7373
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| Exact Mass |
620.299
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| CAS # |
2149584-03-0
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| PubChem CID |
129896979
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| Appearance |
Off-white to light yellow solid powder
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| LogP |
4.6
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| Hydrogen Bond Donor Count |
5
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| Hydrogen Bond Acceptor Count |
6
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| Rotatable Bond Count |
15
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| Heavy Atom Count |
46
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| Complexity |
943
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| Defined Atom Stereocenter Count |
2
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| SMILES |
C1=CC=C(C=C1)C[C@@H](C(=O)N[C@@H](CCCCNC(=O)OCC2C3=CC=CC=C3C4=CC=CC=C24)C(=O)NC5=CC=C(C=C5)CO)N
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| InChi Key |
RCPHMUPZDFKBDS-HEVIKAOCSA-N
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| InChi Code |
InChI=1S/C37H40N4O5/c38-33(22-25-10-2-1-3-11-25)35(43)41-34(36(44)40-27-19-17-26(23-42)18-20-27)16-8-9-21-39-37(45)46-24-32-30-14-6-4-12-28(30)29-13-5-7-15-31(29)32/h1-7,10-15,17-20,32-34,42H,8-9,16,21-24,38H2,(H,39,45)(H,40,44)(H,41,43)/t33-,34-/m0/s1
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| Chemical Name |
9H-fluoren-9-ylmethyl N-[(5S)-5-[[(2S)-2-amino-3-phenylpropanoyl]amino]-6-[4-(hydroxymethyl)anilino]-6-oxohexyl]carbamate
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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) |
DMSO : 100 mg/mL (161.10 mM)
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|---|---|
| Solubility (In Vivo) |
Solubility in Formulation 1: ≥ 2.5 mg/mL (4.03 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL. Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution. Solubility in Formulation 2: ≥ 2.5 mg/mL (4.03 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly. Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution. View More
Solubility in Formulation 3: ≥ 2.5 mg/mL (4.03 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution. |
| Preparing Stock Solutions | 1 mg | 5 mg | 10 mg | |
| 1 mM | 1.6110 mL | 8.0549 mL | 16.1098 mL | |
| 5 mM | 0.3222 mL | 1.6110 mL | 3.2220 mL | |
| 10 mM | 0.1611 mL | 0.8055 mL | 1.6110 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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