| Size | Price | Stock | Qty |
|---|---|---|---|
| 50mg |
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| Other Sizes |
| Targets |
Glutamylcysteine synthetase[1]
The primary target of BSO is γ-glutamylcysteine synthetase (γ-GCS), the rate-limiting enzyme in the glutathione biosynthesis pathway. This enzyme catalyzes the condensation of glutamate and cysteine to form γ-glutamylcysteine, the first step in GSH synthesis. BSO acts as an irreversible inhibitor by binding competitively to the glutamate-binding site at the enzyme's active center, forming a stable enzyme-inhibitor complex (inhibition constant Ki < 100 μM) and irreversibly blocking de novo GSH synthesis. Notably, BSO exhibits exceptional selectivity for γ-GCS, showing no inhibitory activity against glutamine synthetase at concentrations up to 500 μM. DL-Buthionine-(S,R)-sulfoximine hydrochloride targets γ-glutamylcysteine synthetase (glutamylcysteine synthetase), the enzyme responsible for the first and rate-limiting step in glutathione biosynthesis. It induces 100% inhibition at a concentration of 10 μM in enzyme assays and is selective for γ-glutamylcysteine synthetase, lacking activity at glutamine synthetase at concentrations up to 500 μM. |
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| ln Vitro |
Buthionine sulfoximine is a methionine sulfoximine analog that inhibits gamma-glutamylcysteine synthetase more than prothionine sulfoximine by at least 100 times and more than 20 times, respectively[1].
BSO exhibits selective cytotoxic activity against various tumor cell lines in vitro, with particular potency against malignant melanoma cells. Studies have shown that BSO has an IC₅₀ of 1.9 μM against melanoma cells, significantly lower than against breast cancer cells (8.6 μM) and ovarian cancer cells (29 μM). Mechanistically, treatment with 50 μM BSO for 48 hours results in a 95% decrease in GSH levels in melanoma cell lines, a 60% decrease in glutathione S-transferase (GST) enzyme activity, and significant downregulation of GST-π protein and mRNA levels. Additionally, BSO induces ferroptosis in cancer cells, a form of regulated cell death distinct from apoptosis. In vitro, BSO (50 μM, 48 hours) leads to a 95% reduction in GSH levels and a 60% reduction in GST enzyme activity in ZAZ and M14 melanoma cell lines. BSO increases the frequency of DNA deletions in developing mice. By depleting glutathione, it increases cellular sensitivity to oxidative stress and chemotherapeutic agents. |
| ln Vivo |
Continuous intravenous infusion of nontoxic doses of D,L-Buthionine-(S,R)-sulfoximine (300 and 600 mg/kg/day) in mice harboring HT1080 and HT1080/DR4 xenografts results in a 60% decrease in GSH plasma levels and a greater than 95% reduction in GSH tumor levels in both parental and multidrug-resistant tumors[2].
BSO demonstrates both single-agent anti-tumor activity and chemosensitizing effects in in vivo animal models. In mouse models bearing HT1080 fibrosarcoma and multidrug-resistant HT1080/DR4 xenografts, continuous intravenous infusion of non-toxic doses of D,L-BSO (300 and 600 mg/kg/day) produced a 60% reduction in plasma GSH levels and greater than 95% reduction in tumor GSH levels in both parental and multidrug-resistant tumors. Furthermore, BSO exhibits antiparasitic activity by eliminating Trypanosoma brucei from the bloodstream of infected mice through depletion of intratrypanosomal glutathione and induction of oxidative stress at a dose of 4 mmol/kg. In vivo, BSO has been used to study the role of glutathione in various physiological and pathological processes. By depleting glutathione, it modulates cellular redox balance and can sensitize tumors to chemotherapy and radiation. It is used in research models to investigate drug resistance and apoptosis mechanisms. |
| Enzyme Assay |
The inhibitory activity of BSO against γ-glutamylcysteine synthetase can be assessed using enzyme-coupled colorimetric assays. γ-GCS enzyme is purified from rat liver. Various concentrations of BSO (0-500 μM) are pre-incubated with the enzyme in reaction buffer (50 mM Tris-HCl, pH 8.2) containing glutamate, cysteine, ATP, and MgCl₂ at 37°C for 15 minutes to allow irreversible binding of BSO to the enzyme. After substrate addition to initiate the reaction, the rate of absorbance decrease at 340 nm is monitored using an NADH oxidation coupling system to calculate the enzyme activity inhibition rate. It is reported that 10 μM BSO achieves 100% inhibition of γ-GCS in this assay system. The inhibition type and Ki value can be analyzed by Lineweaver-Burk double reciprocal plots.
Non-cellular enzyme assays for BSO involve measuring its inhibitory activity against γ-glutamylcysteine synthetase. The compound is incubated with the enzyme and its substrates, and the inhibition of enzyme activity is quantified to determine the IC50 or percentage inhibition. |
| Cell Assay |
Exponentially growing tumor cells (e.g., melanoma M14 or ZAZ cells) are seeded into 96-well culture plates at densities of 5×10³-1×10⁴ cells/well in medium containing 10% fetal bovine serum and cultured overnight. The following day, various concentrations of BSO (0-500 μM) are added and incubated for 24-72 hours. Cell viability is assessed using MTT or CCK-8 assays. For mechanistic studies, total glutathione levels can be determined using the DTNB method, and GST-π protein expression can be detected by Western blot. Cellular reactive oxygen species levels can be detected using the DCFH-DA fluorescent probe by flow cytometry.
In vitro cellular assays for BSO are performed using various cell lines to assess glutathione depletion and its effects on cellular sensitivity to oxidative stress and chemotherapeutic agents. Cells are treated with BSO, and intracellular GSH levels are measured using colorimetric or fluorometric assays. |
| Animal Protocol |
Six-to-eight-week-old female nude mice are subcutaneously inoculated with tumor cells to establish xenograft models. When tumor volumes reach approximately 100-150 mm³, animals are randomly assigned to treatment groups (6-10 mice per group). BSO is prepared in saline and administered via intraperitoneal injection (32 mmol/kg) or via drinking water. For intravenous infusion, typical doses are 300-600 mg/kg/day. Tumor volume and body weight are measured 2-3 times weekly. At the end of the experiment, animals are euthanized, and tumor tissues are collected for GSH content assays.
In vivo animal experiments for BSO are conducted in mouse models to study the effects of glutathione depletion on drug resistance, tumor sensitization, and oxidative stress. The compound is administered via appropriate routes, and endpoints include measurement of tissue GSH levels and assessment of therapeutic efficacy. |
| ADME/Pharmacokinetics |
The pharmacokinetics of BSO have been characterized in cancer patients in preliminary studies. BSO consists of an equal mixture of R and S diastereoisomers, with S-BSO being the primary active isomer. The two isomers exhibit differential clearance characteristics in vivo: R-BSO clears approximately 25% faster than S-BSO, with a shorter half-life. Renal clearance for both isomers approximates the glomerular filtration rate, accounting for 64% of total S-BSO clearance. Over the dose range of 5-10.5 g/m², the area under the concentration-time curve (AUC) of BSO is linearly related to dose. BSO concentrations in plasma and urine can be quantified by reversed-phase high-performance liquid chromatography.
Pharmacokinetic properties for BSO are not extensively detailed in available sources. The hydrochloride salt form improves solubility and handling in experimental settings. As a small molecule inhibitor, its PK would be influenced by factors such as solubility, metabolic stability, and bioavailability. |
| Toxicity/Toxicokinetics |
BSO exhibits dose-dependent toxicity in animal studies. Following intraperitoneal administration, BSO causes lung changes, liver effects, and maternal reproductive toxicity in rats. In guinea pigs, two weeks of intermittent subcutaneous injection induces diffuse hepatitis. BSO is an irritant to skin and eyes. BSO treatment also causes an elevated frequency of DNA deletions during mouse development: 2 mM BSO treatment results in approximately 30% more DNA deletions, and 20 mM BSO treatment results in 40% more deletions compared to untreated controls. However, the effective GSH-depleting concentration required to achieve IC₉₀ for melanoma (25.5 μM) is 20-fold lower than steady-state plasma concentrations achievable clinically, suggesting a favorable therapeutic window for BSO.
Toxicological data for BSO are limited. BSO increases the frequency of DNA deletions in developing mice. As a research compound, its comprehensive safety profile has not been extensively characterized. It is intended for research use only and not for human consumption. |
| References |
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| Additional Infomation |
DL-Buthionine-(S,R)-sulfoximine hydrochloride is a potent inhibitor of glutamylcysteine synthetase that depletes intracellular glutathione. It is widely used in research to study redox biology, drug resistance, and apoptosis mechanisms. No clinical trial or regulatory approval information is available.
|
| Molecular Formula |
C8H19CLN2O3S
|
|---|---|
| Molecular Weight |
258.77
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| Exact Mass |
258.080491
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| Related CAS # |
DL-Buthionine-(S,R)-sulfoximine;5072-26-4;L-Buthionine-(S,R)-sulfoximine hydrochloride
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| PubChem CID |
138911409
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| Appearance |
Typically exists as solid at room temperature
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| Hydrogen Bond Donor Count |
4
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| Hydrogen Bond Acceptor Count |
5
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| Rotatable Bond Count |
7
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| Heavy Atom Count |
15
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| Complexity |
284
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| Defined Atom Stereocenter Count |
0
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| SMILES |
CCCCS(=N)(=O)CCC(C(=O)O)N.Cl
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| InChi Key |
FMWPIVFRJOQKNQ-UHFFFAOYSA-N
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| InChi Code |
InChI=1S/C8H18N2O3S.ClH/c1-2-3-5-14(10,13)6-4-7(9)8(11)12;/h7,10H,2-6,9H2,1H3,(H,11,12);1H
|
| Chemical Name |
2-amino-4-(butylsulfonimidoyl)butanoic acid;hydrochloride
|
| Synonyms |
DL-Buthionine-(S,R)-sulfoximine (hydrochloride); BSO (hydrochloride); DL-Buthionine-(S,R)-sulfoximine hydrochloride;
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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) |
H2O :~100 mg/mL (~386.44 mM)
DMSO :< 1 mg/mL |
|---|---|
| Solubility (In Vivo) |
Solubility in Formulation 1: 100 mg/mL (386.44 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 | 3.8644 mL | 19.3222 mL | 38.6444 mL | |
| 5 mM | 0.7729 mL | 3.8644 mL | 7.7289 mL | |
| 10 mM | 0.3864 mL | 1.9322 mL | 3.8644 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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