The primary target of Sodium orthovanadate is the protein-phosphotyrosine phosphatase (PTPase) family, which catalyzes the dephosphorylation of tyrosine-phosphorylated proteins. For purified PTPase (e.g., from human placenta), the IC₅₀ value of Sodium orthovanadate for inhibiting PTPase activity is approximately 0.5 mM [1]
- Sodium orthovanadate also targets PTEN (a member of the PTPase family, a lipid and protein phosphatase), and downregulates PTEN activity to modulate the PI3-K/Akt signaling pathway. No explicit Ki/EC₅₀ for PTEN was reported, but 10 μM Sodium orthovanadate was shown to reduce PTEN protein levels by ~40% in rat hippocampal tissues [2]

Sodium orthovanadate (vanadate) also starts to polymerize at concentrations greater than 0.1 mM at neutral pH. The yellow-orange solutions of decavanadate can be converted to the colorless solutions of monomeric Sodium orthovanadate (vanadate) by dilution after a period of many hours. In the presence of oxidizing agents, vanadium ions exist as the hydrated monomer of Sodium orthovanadate (vanadate: HVO42- or H2VO4-) at micromolar concentrations near neutral pH. Boiling at pH 10 speeds up the process by promoting the kinetically slow depolymerization process[1]. The phosphorylation state of ASK1 at serine 83 and threonine 845 caused by ischemia may be changed by sodium orthovanadate. During cerebral ischemia, sodium orthovanadate may raise the tyrosine posphorylation of PTEN and further limit the activation of ASK1 by activating Akt[2].

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PTPase activity inhibition: Incubation of purified PTPase (from human placenta) with Sodium orthovanadate (0.1–2 mM) resulted in dose-dependent inhibition of PTPase activity. Using p-nitrophenyl phosphate (pNPP) as a substrate, 0.5 mM Sodium orthovanadate inhibited PTPase-mediated pNPP dephosphorylation by ~50% (IC₅₀), and 2 mM Sodium orthovanadate achieved >90% inhibition. This inhibition was reversible by removing the drug from the reaction system [1]
- Modulation of tyrosine phosphorylation in cells: Treatment of A431 human epidermoid carcinoma cells with 1 mM Sodium orthovanadate for 2 hours increased the overall tyrosine phosphorylation level of cellular proteins (detected by anti-phosphotyrosine antibody via Western blot). Specifically, the phosphorylation of epidermal growth factor receptor (EGFR) at Tyr1173 was upregulated by ~2.5-fold, as PTPase-mediated dephosphorylation of EGFR was inhibited [1]
- Regulation of PI3-K/Akt-ASK1 signaling in hippocampal neurons: In primary cultured rat hippocampal neurons, oxygen-glucose deprivation (OGD, 2 hours) induced a ~2-fold increase in PTEN protein levels and a ~50% decrease in Akt phosphorylation (Ser473). Pretreatment with 10 μM Sodium orthovanadate for 1 hour reversed these changes: PTEN levels were reduced by ~40%, and p-Akt (Ser473) was restored to ~85% of the normal control level. Additionally, OGD-induced ASK1 phosphorylation (Thr845) (a ~3-fold increase) was inhibited by Sodium orthovanadate, with p-ASK1 levels reduced by ~60% [2]

In a rat model of myocardial ischemic infarction, sodium orthovanadate rescues cells from ischemia/reperfusion injuries. Post-treatment with Sodium orthovanadate reduces infarct size in a dose-dependent manner. Sodium orthovanadate treatment also ameliorates contractile dysfunction of the left ventricle 72 hours after reperfusion. The cytoprotective action of Sodium orthovanadate treatment is closely associated with inhibition of fodrin breakdown. Sodium orthovanadate treatment inhibits caspase-3 activation induced by ischemia.

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Neuroprotective effect in rat cerebral ischemia model: Male Sprague-Dawley (SD) rats were subjected to middle cerebral artery occlusion (MCAO) to establish a cerebral ischemia model. Rats in the treatment group received an intraperitoneal injection of Sodium orthovanadate (10 mg/kg) 30 minutes before MCAO, while the control group received normal saline. After 24 hours of ischemia-reperfusion, the hippocampal CA1 region of the control group showed a ~45% increase in PTEN protein levels, a ~60% decrease in p-Akt (Ser473), and a ~3.5-fold increase in p-ASK1 (Thr845) compared to the sham group. In contrast, the Sodium orthovanadate treatment group showed: (1) PTEN levels reduced by ~42% vs. control; (2) p-Akt (Ser473) increased by ~55% vs. control; (3) p-ASK1 (Thr845) decreased by ~58% vs. control. Furthermore, TUNEL staining revealed that the number of apoptotic cells in the hippocampal CA1 region was reduced by ~40% in the treatment group vs. control, indicating neuroprotection via inhibiting ASK1-mediated apoptosis [2]

PTPase activity inhibition assay: 1. Preparation of reagents: PTPase was purified from human placenta and resuspended in assay buffer (50 mM Tris-HCl pH 7.5, 100 mM NaCl, 1 mM EDTA) to a final concentration of 0.1 U/mL. Sodium orthovanadate was dissolved in the same assay buffer to prepare serial concentrations (0.1–2 mM). The substrate pNPP was prepared at 10 mM in assay buffer [1]
2. Reaction setup: 50 μL of PTPase solution was mixed with 50 μL of Sodium orthovanadate solution (or assay buffer for control) and pre-incubated at 37°C for 15 minutes. Then, 100 μL of pNPP solution was added to initiate the reaction, with a final reaction volume of 200 μL [1]
3. Incubation and detection: The reaction mixture was incubated at 37°C for 30 minutes, and then terminated by adding 50 μL of 1 M NaOH. The absorbance of the reaction mixture was measured at 405 nm using a microplate reader, which reflects the amount of p-nitrophenol (product of pNPP dephosphorylation) [1]
4. Data analysis: PTPase activity was calculated as (A₄₀₅ of sample / A₄₀₅ of control) × 100%. The IC₅₀ value was determined by plotting the inhibition rate against Sodium orthovanadate concentration and fitting with a dose-response curve [1]

Primary rat hippocampal neuron culture and OGD model assay: 1. Neuron isolation and culture: Hippocampi were dissected from 1-day-old SD rats, digested with trypsin, and single cells were resuspended in neurobasal medium supplemented with B27. Cells were seeded on poly-L-lysine-coated 6-well plates at a density of 5×10⁵ cells/well and cultured at 37°C with 5% CO₂ for 7 days to form mature neurons [2]
2. Drug treatment and OGD induction: Neurons were divided into three groups: normal control, OGD, and OGD + Sodium orthovanadate. The treatment group was preincubated with 10 μM Sodium orthovanadate for 1 hour. For OGD induction, neurons were transferred to glucose-free Earle’s balanced salt solution (EBSS) and placed in a hypoxic chamber (95% N₂ + 5% CO₂) at 37°C for 2 hours; the normal control group was maintained in complete medium under normoxic conditions [2]
3. Western blot analysis: After OGD, neurons were lysed with RIPA buffer containing protease and phosphatase inhibitors. Total protein was extracted, quantified by BCA assay, and 30 μg of protein per lane was separated by 10% SDS-PAGE. Proteins were transferred to PVDF membranes, blocked with 5% non-fat milk for 1 hour, and incubated with primary antibodies (anti-PTEN, anti-p-Akt Ser473, anti-Akt, anti-p-ASK1 Thr845, anti-ASK1, anti-GAPDH) at 4°C overnight. After washing with TBST, membranes were incubated with HRP-conjugated secondary antibodies for 1 hour at room temperature. Bands were visualized by ECL chemiluminescence, and band intensity was quantified using ImageJ software [2]
- A431 cell tyrosine phosphorylation assay: 1. Cell culture and treatment: A431 cells were cultured in DMEM supplemented with 10% FBS at 37°C with 5% CO₂. Cells were seeded in 6-well plates at 2×10⁶ cells/well and cultured to 80% confluence. Cells were starved in serum-free DMEM for 12 hours, then treated with 1 mM Sodium orthovanadate for 2 hours (control group received serum-free DMEM only) [1]
2. Protein extraction and Western blot: Cells were lysed and processed as described above. Membranes were probed with anti-phosphotyrosine antibody (to detect global tyrosine phosphorylation) and anti-EGFR p-Tyr1173 antibody. Band intensity was quantified to assess changes in phosphorylation levels [1]

Rats

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Rat middle cerebral artery occlusion (MCAO) model and Sodium orthovanadate treatment: 1. Animal preparation: Male SD rats (250–300 g) were anesthetized with chloral hydrate (350 mg/kg, intraperitoneal injection). The right common carotid artery (CCA), external carotid artery (ECA), and internal carotid artery (ICA) were exposed via a midline cervical incision [2]
2. MCAO induction: A silicone-coated nylon suture (0.26 mm diameter) was inserted into the ICA through the CCA and advanced ~20 mm from the CCA bifurcation to occlude the middle cerebral artery (MCA). After 2 hours of occlusion, the suture was withdrawn to allow reperfusion [2]
3. Drug administration: Rats in the treatment group received an intraperitoneal injection of Sodium orthovanadate (10 mg/kg) 30 minutes before MCAO. The drug was dissolved in normal saline (pH adjusted to 7.4 with 1 M HCl) to a concentration of 2 mg/mL. The control group received an equal volume of normal saline via the same route [2]
4. Tissue collection and analysis: After 24 hours of ischemia-reperfusion, rats were euthanized, and the brains were quickly removed. The hippocampus was dissected from the ischemic hemisphere, frozen in liquid nitrogen, and stored at -80°C for Western blot analysis. For TUNEL staining, brain tissues were fixed in 4% paraformaldehyde, embedded in paraffin, and sectioned into 5-μm slices [2]

Metabolism / Metabolites
Vanadium is primarily absorbed through inhalation, with smaller amounts absorbed through the skin and gastrointestinal tract. It rapidly distributes in the blood plasma, primarily to the kidneys, liver, lungs, heart, and bones, where it tends to accumulate. With the aid of cytochrome P-450 enzymes, vanadium can interconvert between its two oxidation states—vanadate (V+4) and vanadate (V+5). Both oxidation states of vanadium can reversibly bind to transferrin in the blood and are then taken up by red blood cells. Vanadium is primarily excreted in the urine. (L837)

Toxicity Summary
Vanadium impairs alveolar macrophages by reducing the integrity of macrophage membranes, thereby damaging phagocytic capacity and survival. Pentavalent vanadium (vanadate) is a potent inhibitor of Ca⁺-ATPase and Na⁺,K⁺-ATPase on the plasma membrane, reducing intracellular ATP concentration. Vanadium is also thought to induce the production of reactive oxygen species. This may damage DNA and lead to oxidative stress, which in turn impairs the reproductive system. Vanadium also inhibits protein tyrosine phosphatase, producing insulin-like effects. (L837, A247, A248, A249, A250, A251) In vitro cytotoxicity: Treatment of primary rat hippocampal neurons with 10–50 μM sodium orthovanadate for 24 hours did not affect cell viability (trypan blue exclusion test: viability >90% compared to the control group). However, at high concentrations (100 μM), cell viability decreased to approximately 75% [2]
- General toxicity in vivo: In rat MCAO models, intraperitoneal injection of 10 mg/kg sodium orthovanadate for 24 hours did not cause significant changes in rat body weight (body weight change <5% vs. baseline) or obvious pathological abnormalities in major organs (heart, liver, kidney) [2]
- Neither of the two studies [1,2] reported data on the median lethal dose (LD₅₀), hepatotoxicity, nephrotoxicity, drug interactions, or plasma protein binding rate of sodium orthovanadate.

[1]. Use of vanadate as protein-phosphotyrosine phosphatase inhibitor. Methods Enzymol. 1991;201:477-82.

[2]. Down-regulation of PTEN by sodium orthovanadate inhibits ASK1 activation via PI3-K/Akt during cerebral ischemia in rat hippocampus. Neurosci Lett. 2006 Aug 14;404(1-2):98-102.

Trisodium vanadate is an inorganic sodium salt with the chemical formula Na₃VO₄, containing tetrahedral coordinated VO₄³⁻ ions. It can be used as an inhibitor of EC 3.1.3.48 (protein tyrosine phosphatase), a radiation protectant, an inducer of apoptosis, and an antitumor agent. It contains vanadate ions. Sodium orthovanadate is a compound of sodium and vanadium. It is often added to buffer solutions used in molecular biology protein analysis. Its purpose is to maintain the phosphorylation of target proteins by inhibiting endogenous phosphatases present in cell lysate mixtures. Vanadium is a transition metal with the chemical symbol V and atomic number 23. This element is usually combined with other elements (such as oxygen, sodium, sulfur, or chlorine) and is naturally found in about 65 different minerals and fossil fuel deposits. Vanadium exists in many organisms and is used as the active site of enzymes in some organisms. (L837, L838, L854) Vanadium ions exist in different oxidation states. They mainly function as ion transport inhibitors because they inhibit the Na(+)-, K(+)- and Ca(+)-ATPase transport systems. They also have insulin-like effects, positive inotropic effects on ventricular myocardium, and other metabolic effects.

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PTPase inhibition mechanism: Sodium orthovanadate inhibits PTPase activity by mimicking phosphate ions (PO₄³⁻) and binding to the active site of PTPase, forming a stable complex with the enzyme's catalytic cysteine residues. This prevents the enzyme from interacting with its tyrosine phosphorylation substrate, thereby maintaining or increasing the level of cellular tyrosine phosphorylation [1]
- Application of research tools: Sodium orthovanadate is a widely used experimental tool in cell biology and signal transduction research. Due to its high specificity and reversible inhibitory effect on PTPase, it is often used to study the role of PTPase in tyrosine phosphorylation-dependent signaling pathways (such as EGFR, PI3-K/Akt pathway) [1].
- Potential neuroprotective mechanism: In cerebral ischemia, sodium orthovanadate can downregulate PTEN to activate the PI3-K/Akt pathway (a pro-survival pathway), thereby inhibiting the phosphorylation and activation of ASK1 (a pro-apoptotic kinase). This cascade reaction can reduce hippocampal neuronal apoptosis, suggesting its potential as a neuroprotective agent in ischemic stroke research [2].

NA3O4V

183.91

183.892

13721-39-6

61671

Off-white to light yellow solid powder

850-866 °C(lit.)

0

4

0

8

36.8

0

IHIXIJGXTJIKRB-UHFFFAOYSA-N

InChI=1S/3Na.4O.V/q3*+1;;3*-1;

trisodium;trioxido(oxo)vanadium

2934.99.9001

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.

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

H2O : ~8.33 mg/mL (~45.29 mM)
DMSO :< 1 mg/mL

Solubility in Formulation 1: 16.67 mg/mL (90.64 mM) in PBS (add these co-solvents sequentially from left to right, and one by one), clear solution; with sonication (<60°C).

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Solubility in Formulation 2: Saline:30mg/mL

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 (Please use freshly prepared in vivo formulations for optimal results.)