Griffin:Sodium Orthovanadate Activation
Sodium Orthovanadate Activation
Sodium orthovanadate should be activated for maximal inhibition of protein phosphotyrosyl-phosphatases.
Prepare a 200 mM solution of sodium orthovanadate.
I. Adjust the pH to 10.0 using either 1N NaOH or 1N HCl. The starting pH of the sodium orthovanadate solution may vary with lots of the chemical. At pH 10.0 the solution will be yellow.
II. Boil the solution until it turns colorless (approximately 10 minutes).
III. Cool to room temperature.
IV. Readjust the pH to 10.0 and repeat steps 3 and 4 until the solution remains colorless and the pH stabilizes at 10.0.
V. Store the activated sodium orthovanadate as aliquots at -20°C.
This procedure depolymerizes the vanadate, converting it into a more potent inhibitor of protein tyrosine phosphatases. Please note that adding DTT rapidly inactivates sodium orthovanadate.