– Inositol monophosphatase 2, also known as Inositol-1(or 4)-monophosphatase 2, Myo-inositol monophosphatase A2 and IMPA2, is an enzyme which belongs to the inositol monophosphatase family. IMPA2 catalyzes the dephosphoylration of inositol monophosphate with cofactor Magnesium and Inhibited by high Li+ and restricted Mg2+ concentrations. IMPA2 plays an important role in phosphatidylinositol signaling. IMPA2 can use the myo-inositol monophosphates, scylloinositol 1,4-diphosphate, glucose-1-phosphate, beta-glycerophosphate, and 2′-AMP as substrates. IMPA2 is a pharmacological target for lithium Li(+) action in brain, it is considered to have a role in schizophrenia and bipolar disorder.