| 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 |
This peptide is used as an analytical marker for infliximab. It originates from the monoclonal antibody structure and is not itself a therapeutic agent, but serves as a tool for quantitation of the parent biologic drug.
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| ln Vitro |
Anti-TNF antibodies obstruct the effects of TNF alpha, a novel therapy for TNF-related disorders, including rheumatoid arthritis, psoriatic arthritis, ulcerative colitis, ankylosing spondylitis, and inflammatory bowel disease. Anti-TNF antibodies stimulate mucosal healing and long-term remissions in vivo by blocking TNF activity. The primary anti-TNF antibodies that are now approved include Golimumab, Adalimumab, Certolizumab, Etanercept, and Infliximab[1].
The peptide itself does not possess direct therapeutic activity. Its utility lies in its ability to serve as a surrogate marker for the presence and quantity of infliximab in biological samples. Infliximab, the parent antibody, specifically binds to and neutralizes tumor necrosis factor-alpha (TNF-alpha). |
| ln Vivo |
LEESGGGLVQPGGSMK acetate is used in ex vivo applications for the quantitative analysis of infliximab levels. It enables monitoring of therapeutic antibody concentrations in patients receiving infliximab for TNF-related disorders including rheumatoid arthritis, psoriatic arthritis, Crohn's disease, and ulcerative colitis.
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| Enzyme Assay |
Non-cell binding assays are performed using purified LEESGGGLVQPGGSMK peptide to validate antibody-analyte interactions. Surface plasmon resonance (SPR) can be used to characterize the binding between the peptide and an anti-peptide capture antibody. The peptide is immobilized on a CM5 sensor chip using amine coupling chemistry to achieve 100-500 response units (RU). Increasing concentrations of detection antibody (0.1-100 nM) are flowed over the chip and the association and dissociation phases are monitored, with data fitted to a 1:1 binding model. Alternatively, ELISA is performed with the peptide coated onto 96-well plates (1-5 ug/mL in PBS overnight at 4degC), blocked with 3% BSA, and incubated with anti-peptide primary antibody, followed by HRP-conjugated secondary antibody and TMB substrate. Absorbance at 450 nm is measured to quantify specific binding.
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| Cell Assay |
Cellular assays using this proteolytic peptide are limited due to its role as an analytical standard rather than a biologically active compound. For the parent infliximab antibody, cellular assays include measuring TNF-alpha neutralization using L929 mouse fibroblast cells. L929 cells are seeded in 96-well plates (3×10⁴ cells/well) and treated with TNF-alpha (10-100 pg/mL) in the presence or absence of infliximab standard. After 24-48 hours, cell viability is assessed by crystal violet staining or MTT assay, and the neutralization titer is determined as the dilution that protects 50% of cells from TNF-alpha-induced cytotoxicity. For immunogenicity assays, PBMCs are isolated from human blood and incubated with infliximab, and T-cell proliferation is measured by [3H]-thymidine incorporation or anti-drug antibody (ADA) levels are quantified by bridging ELISA.
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| Animal Protocol |
LEESGGGLVQPGGSMK acetate itself is not used in animal experiments as it is an analytical tool. For the parent antibody infliximab, in vivo studies are conducted in murine disease models. For rheumatoid arthritis models, 6-8 week old female DBA/1J mice are immunized with bovine type II collagen emulsified in complete Freund's adjuvant (CFA) to induce collagen-induced arthritis (CIA). Infliximab is administered intraperitoneally at 10-20 mg/kg starting at disease onset, every 3-4 days. Arthritis severity is scored clinically on a scale of 0-4 per paw based on erythema and swelling. Paw thickness is measured with calipers. At study termination, joints are harvested for histopathological analysis of inflammation, pannus formation, cartilage damage, and bone erosion. For inflammatory bowel disease models (e.g., DSS-induced colitis), mice receive 3-5% dextran sodium sulfate (DSS) in drinking water for 5-7 days with infliximab treatment given IP, and disease activity is monitored by body weight loss, stool consistency, and fecal bleeding.
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| ADME/Pharmacokinetics |
As an analytical reference peptide, the pharmacokinetics of LEESGGGLVQPGGSMK acetate are not studied in isolation. The parent antibody infliximab has a pharmacokinetic profile characterized by slow clearance and a long terminal elimination half-life of approximately 7-12 days in humans following intravenous infusion. The volume of distribution is small (approximately 3-4 L), consistent with confinement to the vascular space. Bioavailability is 100% for IV administration. Infliximab is metabolized via proteolytic degradation into small peptides and amino acids rather than through CYP450 pathways. The presence of anti-drug antibodies (ADAs) can significantly accelerate clearance, reducing the half-life to 3-6 days. The therapeutic trough concentration range for infliximab in inflammatory bowel disease is typically 3-7 ug/mL.
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| Toxicity/Toxicokinetics |
No specific toxicity data exists for the proteolytic peptide fragment. The parent infliximab antibody has well-characterized safety profiles from extensive clinical use. Common adverse effects include infusion-related reactions (fever, chills, urticaria, dyspnea) occurring in approximately 20% of patients, upper respiratory infections, and reactivation of latent tuberculosis. More serious toxicities include opportunistic infections (histoplasmosis, coccidioidomycosis, listeriosis), demyelinating disorders, lupus-like syndrome, and hepatotoxicity. Infliximab carries a black box warning for serious infections and malignancy including lymphoma. The LD50 is not applicable for therapeutic monoclonal antibodies.
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| References | |
| Additional Infomation |
This peptide serves as a valuable tool for bioanalysis of infliximab, enabling therapeutic drug monitoring (TDM) to optimize dosing regimens. LEESGGGLVQPGGSMK acetate is typically used as a quantitative standard in liquid chromatography-mass spectrometry (LC-MS/MS) methods for measuring infliximab concentrations in patient serum or plasma. Following tryptic digestion of serum samples, this unique peptide is released from the infliximab antibody and quantified against a calibration curve prepared from the synthetic peptide standard. The approach is essential for pharmacokinetic studies, bioequivalence assessments, and clinical TDM applications. Infliximab, which the peptide originates from, has been approved by the FDA (1998) and EMA for treatment of Crohn's disease, ulcerative colitis, rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis, and plaque psoriasis.
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| Molecular Formula |
C66H112N18O26S
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| Molecular Weight |
1605.76
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| Related CAS # |
LEESGGGLVQPGGSMK;2096980-79-7;LEESGGGLVQPGGSMK TFA
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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 (~62.28 mM)
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| Solubility (In Vivo) |
Solubility in Formulation 1: 100 mg/mL (62.28 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 | 0.6228 mL | 3.1138 mL | 6.2276 mL | |
| 5 mM | 0.1246 mL | 0.6228 mL | 1.2455 mL | |
| 10 mM | 0.0623 mL | 0.3114 mL | 0.6228 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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