| Size | Price | Stock | Qty |
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| 1mg |
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| Other Sizes |
| Targets |
Not applicable. N-Ac-gamma-Calicheamicin-AcBut-NHS ester is an ADC linker-payload conjugate, not a free drug with a specific biological receptor target. The calicheamicin moiety binds to the minor groove of DNA and undergoes a rearrangement to generate a diradical species that abstracts hydrogen atoms from the deoxyribose backbone, resulting in sequence-selective DNA double-strand breaks. This DNA-damaging mechanism is not mediated by a protein target.
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| ln Vitro |
N-Ac-gamma-Calicheamicin-AcBut-NHS ester is an ADC toxic molecule that induces cell cycle arrest and apoptosis by inducing DNA double-strand breaks. This mechanism makes it highly potent against rapidly dividing cancer cells. The compound is a derivative of calicheamicin, a natural product enediyne antibiotic first isolated from Micromonospora echinospora. Its potency in vitro is demonstrated by its use as the cytotoxic payload in the clinically approved ADC gemtuzumab ozogamicin (Mylotarg) for the treatment of acute myeloid leukemia (AML).
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| ln Vivo |
N-Ac-gamma-Calicheamicin-AcBut-NHS ester demonstrates anti-cancer activity in both in vitro and in vivo models, particularly against hematological malignancies such as acute lymphoblastic leukemia (ALL) and other blood cancers. When conjugated to a targeting antibody (e.g., gemtuzumab targeting CD33), the ADC binds to cancer cell surface antigens, is internalized, and releases the calicheamicin payload, leading to selective killing of cancer cells. This approach has been clinically validated with gemtuzumab ozogamicin.
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| Enzyme Assay |
Not applicable. The DNA-cleavage activity of the calicheamicin payload is typically evaluated in cell-free DNA nicking assays. Standard protocol: Plasmid DNA (pBR322 or supercoiled pUC19, 0.5 ug) is incubated with calicheamicin derivative (0.1-100 uM) in 20 uL of TE buffer (10 mM Tris-HCl pH 7.5, 1 mM EDTA). After incubation at 37degC for 30-60 minutes, the reaction is stopped by adding loading buffer. DNA is resolved on a 1% agarose gel, stained with ethidium bromide, and visualized under UV light. Conversion of supercoiled DNA to nicked circular and linear forms indicates DNA double-strand breaks.
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| Cell Assay |
Standard cellular cytotoxicity assay for ADC payload evaluation: Cancer cell lines (e.g., HL-60, THP-1, or MOLT-4 leukemia cells) are seeded in 96-well plates in RPMI-1640 medium with 10% FBS. Cells are treated with N-Ac-gamma-Calicheamicin-AcBut-NHS ester (as a free cytotoxin or conjugated to an antibody) at concentrations ranging from 0.0001-1000 nM for 72 hours. Cell viability is measured using CellTiter-Glo luminescent assay or MTT assay. The IC50 is calculated from the dose-response curve. DNA fragmentation can be assessed by TUNEL assay or by gel electrophoresis.
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| Animal Protocol |
No specific animal protocol is provided. A typical in vivo efficacy study for an ADC using this payload: Female SCID or NSG mice (6-8 weeks old) are injected intravenously with 1×10⁶ leukemia cells (e.g., MOLT-4 or HL-60). After engraftment (5-14 days), mice are randomized into treatment groups (n=8-10/group). The ADC is administered intravenously at doses of 0.1-10 mg/kg once weekly for 2-4 weeks. Tumor burden is monitored by bioluminescence (if cells are luciferase-labeled) or by flow cytometry of peripheral blood for human CD45+ cells. Survival is recorded as the primary endpoint.
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| ADME/Pharmacokinetics |
No specific PK data is available for the unconjugated payload. When conjugated in an ADC, the PK is determined by the antibody. Calicheamicin-based ADCs are administered intravenously and have a terminal half-life of approximately 2-4 days in humans (for gemtuzumab ozogamicin). The payload is released after ADC internalization and lysosomal degradation. The free calicheamicin derivative has a very short half-life in circulation (minutes to hours).
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| Toxicity/Toxicokinetics |
Calicheamicin and its derivatives are highly toxic DNA-cleaving agents. As ADC payloads, they are not administered as free drugs due to their extreme potency and off-target toxicity. In preclinical studies, unconjugated calicheamicin derivatives are associated with significant toxicity including hepatotoxicity, myelosuppression (due to DNA damage in bone marrow), and vascular leak syndrome. The tetrasulfide linker used in calicheamicin-based ADCs is designed for controlled intracellular release.
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| References | |
| Additional Infomation |
N-Ac-gamma-Calicheamicin-AcBut-NHS ester (CAS: 174885-02-0) has molecular formula C77H99IN6O28S3 and molecular weight 1779.73. Appearance: White to off-white solid powder. It is an ADC cytotoxin that induces DNA double-strand breaks leading to cell cycle arrest and apoptosis. It is the drug-linker conjugate used in the clinically approved ADC gemtuzumab ozogamicin (Mylotarg). Soluble in DMSO (≥50 mg/mL). For research use only, not for human therapeutic applications.
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| Molecular Formula |
C77H99IN6O28S3
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|---|---|
| Molecular Weight |
1779.73
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| CAS # |
174885-02-0
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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 (e.g. under nitrogen), avoid exposure to moisture and light. |
| 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 : ≥ 50 mg/mL (~28.09 mM)
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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.) |
| Preparing Stock Solutions | 1 mg | 5 mg | 10 mg | |
| 1 mM | 0.5619 mL | 2.8094 mL | 5.6188 mL | |
| 5 mM | 0.1124 mL | 0.5619 mL | 1.1238 mL | |
| 10 mM | 0.0562 mL | 0.2809 mL | 0.5619 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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