I4P is dephosphorylated to Ins by IMPA1/2 in the cytosol

Inositol monophosphatase 1 (IMPA1) and 2 (IMPA2) homodimers dephosphorylate inositol 4-phosphate (I4P) to inositol (Ins). In vitro, IMPA1 and 2 differ in their pH optima and IMPA1 has a significantly greater activity on IP4 than does IMPA2 (Ohnishi et al. 2007).

肌醇单磷酸酶1（Inositol monophosphatase 1，简称IMPA1）和2（Inositol monophosphatase 2，简称IMPA2）同源二聚体通过去磷酸化肌醇4-磷酸（Inositol 4-phosphate，简称I4P）转化为肌醇（Inositol，简称Ins）。在体外实验中，IMPA1和IMPA2的pH最适值存在差异，且IMPA1对肌醇1,4-二磷酸（Inositol 1,4-bisphosphate，简称IP4）的活性显著高于IMPA2（Ohnishi等人，2007年）。