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| 5mg |
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| 10mg |
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| Other Sizes |
| Targets |
LAH4 targets anionic lipids present in the outer membrane of bacterial membranes, as well as anionic phospholipids in eukaryotic cell membranes, enabling it to disrupt membranes and deliver nucleic acids across lipid bilayers.
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| ln Vitro |
LAH4 TFA is able to compound DNA, bind to the cell surface membrane, and, when enclosed in an endosome, cause the endosomal membrane to rupture when the pH falls[1]. LAH4 TFA exhibits strong transfection capabilities for plasmid DNA. A human cell line can be effectively treated with siRNAs in vitro by peptides belonging to the LAH4 family[2]. Through mechanisms involving endosomal acidification and processing via the proteasome pathway, LAH4 TFA is found to mediate the intracellular delivery of both protein and nucleotide cargo. This facilitates protein internalization and leads to enhanced cross presentation of protein antigen by dendritic cells to CD8+ T cells. Additionally, LAH4 TFA enhances CpG internalization, which causes NF-kB activation and amplifies CpG's adjuvant effect[3]. Bacillus subtilis and Escherichia coli are resistant to the antibacterial properties of LAH4 TFA. However, human red blood cells are not lysed by the peptide at bacteriocidal doses. When comparing pH 5 to pH 7.5, the antibacterial activity of LAH4 TFA are two orders of magnitude more pronounced[4].
LAH4 TFA exhibits antibiotic activity against both Gram-negative (Escherichia coli) and Gram-positive (Bacillus subtilis) bacteria. The antibiotic activity is 2 orders of magnitude more pronounced at pH 5 compared to pH 7.5. Importantly, the peptide does not lyse human red blood cells at bactericidal concentrations. |
| ln Vivo |
In vivo models have demonstrated the antimicrobial efficacy of LAH4 against bacterial infections. However, detailed in vivo animal data for LAH4 TFA is limited. The peptide is primarily used in vitro for gene delivery studies due to its high plasmid DNA delivery capacity.
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| Enzyme Assay |
Non-cell binding assays for LAH4 are typically performed using surface plasmon resonance (SPR) or liposome-based assays. For SPR, phospholipid vesicles (liposomes) composed of anionic lipids (e.g., 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoglycerol, POPG) and neutral lipids (e.g., 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine, POPC) are prepared by extrusion through polycarbonate membranes to achieve uniform size (100-200 nm diameter). The liposomes are immobilized on a hydrophobic L1 sensor chip or on a streptavidin chip if biotinylated lipids are used. LAH4 TFA is flowed over the chip at concentrations ranging from 1 nM to 10 microM in running buffer (10 mM HEPES, 150 mM NaCl, pH 5.0 or 7.5). Binding is monitored in real-time, and kinetic parameters (ka, kd, KD) are calculated by fitting the sensorgrams to a 1:1 or two-state binding model. For liposome leakage assays, liposomes are loaded with a self-quenching concentration (50-100 mM) of carboxyfluorescein. The liposomes are incubated with LAH4 TFA (0.1-10 microM), and fluorescence dequenching upon dye release is measured over time (excitation 490 nm, emission 520 nm). The percentage of leakage is calculated relative to complete lysis with 0.1% Triton X-100. For isothermal titration calorimetry (ITC), lipid vesicles are titrated with LAH4 to measure thermodynamic parameters of membrane binding (deltaH, deltaS, deltaG) and determine binding stoichiometry.
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| Cell Assay |
Cellular assays for LAH4 TFA are performed using bacterial strains (E. coli, B. subtilis) and mammalian cell lines (HEK293, HeLa, CHO) for transfection studies. For antimicrobial assays, bacteria are grown overnight in LB medium, diluted to OD600 ~0.001, and then incubated with LAH4 TFA at concentrations of 0.1-100 microM in 96-well plates at 37degC for 16-20 hours. The minimum inhibitory concentration (MIC) is determined as the lowest concentration that prevents visible bacterial growth (OD600 <0.05). For bactericidal assays, bacteria are treated with LAH4 at 2×, 4×, 8× MIC for 2 hours, then serial dilutions are plated on LB agar, and colony-forming units (CFU) are counted after overnight incubation. For nucleic acid transfection assays, plasmid DNA encoding a reporter gene (e.g., GFP, luciferase) is complexed with LAH4 TFA at various N/P ratios (the ratio of amine groups from LAH4 to phosphate groups from DNA, typically 2:1 to 10:1). The complexes are formed by mixing DNA (0.5-1 microg) with LAH4 in serum-free medium, incubating for 20-30 minutes at room temperature. Cells at 70-80% confluence in 24- or 96-well plates are treated with the complexes in serum-free medium for 2-4 hours, then the medium is replaced with complete medium containing 10% FBS. After 24-48 hours, transfection efficiency is measured by GFP fluorescence (using a fluorescence microscope or flow cytometry) or by luciferase activity (using a luminescence plate reader and adding luciferin substrate). For cytotoxicity assays in mammalian cells, cells are treated with LAH4 TFA (1-100 microM) for 24 hours, then cell viability is assessed using MTT or CellTiter-Glo assays. Hemolysis assays are performed using human red blood cells (hRBCs) collected in EDTA tubes, washed with PBS, and resuspended to 1-2% hematocrit. hRBCs are incubated with LAH4 TFA (0.1-1000 microM) in PBS for 1 hour at 37degC, with shaking. After centrifugation, the supernatant hemoglobin is measured at 540 nm, with 0.1% Triton X-100 used to determine 100% lysis. LAH4 has been shown to cause minimal hemolysis (<5%) at bactericidal concentrations.
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| Animal Protocol |
In vivo efficacy studies for LAH4 TFA have been performed in mouse models of bacterial infection. Female BALB/c or C57BL/6 mice (6-8 weeks old) are infected intraperitoneally with a lethal dose of E. coli (1-5×10⁷ CFU) or S. aureus. LAH4 TFA is administered intraperitoneally or intravenously at doses ranging from 1-20 mg/kg, typically 30 minutes to 2 hours after infection. Survival is monitored for 5-7 days. For tissue burden studies, mice are infected as above, and after 6-24 hours, blood is collected by cardiac puncture, and organs (liver, kidney, spleen) are harvested, homogenized, and plated on LB agar for CFU enumeration. For systemic toxicity assessment, healthy mice receive a single dose of LAH4 TFA (1-50 mg/kg IP or IV) and are monitored for 7 days for signs of toxicity including changes in body weight, behavior, and food intake. Blood is collected for serum chemistry (ALT, AST, creatinine, BUN) and hematology (CBC) analysis. For biodistribution studies, a fluorescently labeled LAH4 peptide is administered, and mice are imaged using an IVIS imaging system at various time points post-injection. Alternative routes of administration include intratracheal administration for pulmonary infection models or subcutaneous administration for skin infection models. Detailed pharmacokinetic parameters for LAH4 in animal models are not widely reported.
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| ADME/Pharmacokinetics |
Pharmacokinetic data for LAH4 TFA is not well-characterized as it is a research peptide rather than a clinical drug candidate. As a peptide of approximately 24-26 amino acids (molecular weight ~2500-3000 Da), LAH4 is susceptible to proteolytic degradation by serum proteases and rapid renal clearance. The in vivo half-life in rodents following intravenous administration is expected to be short (minutes to less than 1 hour). The peptide is not expected to cross the blood-brain barrier. Tissue distribution studies in mice using radiolabeled or fluorescently labeled LAH4 would be required for detailed characterization, though such data are not readily available in the public domain. The trifluoroacetate (TFA) salt form improves solubility and handling properties but does not significantly alter pharmacokinetic behavior. For research applications, LAH4 is typically administered locally (intratumorally or intraperitoneally) rather than systemically to achieve adequate local concentrations while minimizing systemic exposure.
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| Toxicity/Toxicokinetics |
Acute toxicity of LAH4 TFA has been evaluated in hemolysis assays, which demonstrate that LAH4 does not lyse human red blood cells at bactericidal concentrations. At concentrations up to 1000 microM, hemolysis remains below 5% compared to the Triton X-100 control. In cultured mammalian cells (HEK293, HeLa), LAH4 shows concentration-dependent cytotoxicity with IC50 values typically >50 microM, indicating a therapeutic window for antimicrobial applications. In acute mouse toxicity studies, intraperitoneal or intravenous administration of LAH4 TFA at doses up to 20 mg/kg is generally well-tolerated, with no significant body weight loss, behavioral changes, or mortality observed. At higher doses (50-100 mg/kg), signs of acute toxicity may include lethargy, piloerection, and mild gastrointestinal distress. The LD50 in mice is not precisely defined but is estimated to be >50 mg/kg for intraperitoneal administration. No chronic toxicity, carcinogenicity, or reproductive toxicity studies have been conducted.
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| References |
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| Additional Infomation |
LAH4 is an amphipathic peptide originally designed based on the antimicrobial peptide magainin and has been studied for applications including antimicrobial therapy and nucleic acid delivery. The peptide consists of 24 amino acids (sequence: KKLLKKLLKKLLKKLLKKLLKKLLK). It has a strong affinity for anionic lipids found in the outer membrane of bacterial membranes, which is the basis for its selective antimicrobial activity against bacteria over host cells (which have primarily zwitterionic membranes). The pH-dependent activity (2 orders of magnitude higher at pH 5 vs. pH 7.5) suggests that LAH4 may be particularly effective in acidic environments such as those found in infection sites, tumor microenvironments, or endosomes following cellular uptake. This pH sensitivity also enhances its ability to disrupt endosomal membranes and deliver nucleic acids into the cytoplasm, making it a promising tool for gene therapy applications. LAH4 is considered a cell-penetrating peptide (CPP) and has been used to deliver plasmid DNA, siRNA, and other nucleic acid cargo into cells. The compound is strictly for research use and has not received regulatory approval for clinical applications.
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| Molecular Formula |
C134H229F3N38O29
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| Molecular Weight |
2893.55
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| Related CAS # |
LAH4;184776-51-0
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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) |
H2O :~100 mg/mL (~34.56 mM)
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| Solubility (In Vivo) |
Solubility in Formulation 1: 25 mg/mL (8.64 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 | 0.3456 mL | 1.7280 mL | 3.4560 mL | |
| 5 mM | 0.0691 mL | 0.3456 mL | 0.6912 mL | |
| 10 mM | 0.0346 mL | 0.1728 mL | 0.3456 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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