Sodium orthovanadate is a chemical compound of sodium and vanadium. It is often added to buffer solutions that are used in protein analysis in molecular biology. The aim is to preserve the phosphorylation of proteins of interest by inhibiting endogenous phosphatases present in cell lysate mixture. Vanadium is a transition metal with the chemical symbol V and atomic number 23. The element usually combines with other elements such as oxygen, sodium, sulfur, or chloride, and occurs naturally in about 65 different minerals and in fossil fuel deposits. Vanadium is found in many organisms, and is used by some life forms as an active center of enzymes.