Sodium orthovanadate

Vanadate (sodium orthovanadate or peroxovanadate) exhibits insulin-like effects in vitro (activation of insulin receptor tyrosine kinase, PI 3-kinase, Akt) and in vivo (diabetic rats, humans). These effects can be explained at least in part by the inhibition of phosphotyrosine phosphatases which deactivate the INSR tyrosine kinase. 

Useful serine/threonine protein phosphatase inhibitors include microcystin-LR (which inhibits protein phosphatases 1, 2A, and 2C, and related enzymes) and /1-glycerophosphate. Sodium fluoride may also be employed. Sodium orthovanadate inhibits protein tyrosine phosphatases. 

Lead Orthovanadaie, Pb3(V04)2, is precipitated as a white powder when sodium orthovanadate is treated with lead acetate solution.7... 

Silver Ortliovanadate, Ag3V04, is precipitated as a deep orange powder when a freshly prepared solution of sodium orthovanadate is treated with a carefully neutralised solution of silver nitrate. It melts between 408° and 565° C.,7 and is soluble in nitric acid and in ammonium hydroxide the latter solution yields yellow hexagonal crystals of the composition 3AgV03.2NH3.H20.8... 

Sodium Orthovanadate, Na3V04.12H20, is the orthovanadate most frequently met with. It is readily obtained by adding excess of caustic soda to a solution of sodium pyrovanadate ... 

Sodium Stannovanadates or Vanadostannates.—By crystallising mixed solutions of sodium stannate and sodium orthovanadate, a series of sodium stannovanadates has been prepared, the salts having the following compositions —... 

When a solution containing sodium orthovanadate and stannous chloride is carefully neutralised with caustic soda, an amorphous yellow substance is obtained which has the composition... 

Thallium Pyrovanadate, T14V20 is precipitated as a light yellow powder by the addition of thallium sulphate to a cold, saturated solution of sodium orthovanadate. It also results on fusing a mixture of vanadium pentoxide and thallium carbonate.14 It melts at 454°15 or 416° C.,16 and is soluble in about 5000 parts of water at 14° C. 

Sodium Orthoxytrithiovanadate, Na8VS30.5H20, is obtained in dark, reddish-brown, deliquescent crystals by the action of sodium hydrosulphide on sodium pyrovanadate. The anhydrous salt is formed when vanadium pentoxide, sulphur and sodium carbonate are fused together,4 or by the action of hydrogen sulphide on sodium orthovanadate at 500° to 700° C.5... 

Vanadate. Sodium vanadate, sodium orthovanadate, Na3V04, white solid, soluble, formed by fusion of vanadium pentoxide and sodium carbonate. Used (1) in inks, (2) in photography, (3) in dyeing of furs, (4) in inoculation of plant life. 

Morita, A., J. Zhu, N. Suzuki, A. Enomoto, Y. Matsumoto, M. Tomita, T. Suzuki, K. Ohtomo, and Y. Hosoi. 2006. Sodium orthovanadate suppresses DNA damage-induced caspase activation and apoptosis by inactivating p53. Cell Death Differ. 13 499-511. 

Aguirre, M.V., J.A. Juaristi, M.A. Alvarez, and N.C. Brandan. 2005. Characteristics of in vivo murine erythropoietic response to sodium orthovanadate. Chemico-Biolog. Interact. 156 55-68. 

Kawano, T., Fukunaga, K., Takeuchi, Y., Morioka, M., Yano, S., Hamada, J., Ushio, Y., and Miyamoto, E. (2001). Neuroprotective effect of sodium orthovanadate on delayed neuronal death after transient forebrain ischemia in gerbil hippocampus. J. Cereb. Blood Flow Metab. 21,... 

Assay volumes usually range from 3 pL (for 1536-well MTPs) to 50 pL (384-well MTPs). Within a given total assay volume, smaller volumes of reagents are added. Frequently, we find it convenient to add reagents into the assay in equivalent volumes of assay buffer. As an example, for a 15-pL assay, one might add 5 pL of compound solution, 5 pL of enzyme stock solution, 5 pL of substrate mix, followed by 10 pL of quench solution in a stop buffer. For kinase assays, the stop buffer may be EDTA and for phosphatase assays, sodium orthovanadate. 

Vanadate solutions are usually prepared from sodium orthovanadate, Na3V04, or sodium metavanadate, NaV03, or from the corresponding ammonium salts. These give the same vanadate species in solution after equilibration. In vitro assays of the effect of vanadate reported in the literature have used a wide range of concentrations, ca 10 mM to 1 nM. It is instructive to examine the species of vanadate which are expected to be present under conditions of equilibrium at these concentrations of vanadium. 

---