Phosphatase with broad specificity; it can dephosphorylate fructose 1,6-bisphosphate, both D and L isomers of inositol-1-phosphate (I-1-P), 2'-AMP, pNPP, inositol-2-phosphate, beta-glycerol phosphate, and alpha-D-glucose-1-phosphate. Cannot hydrolyze glucose-6-phosphate and fructose-6-phosphate. May be involved in the biosynthesis of a unique osmolyte, di-myo-inositol 1,1-phosphate. beta-D-fructose 1,6-bisphosphate + H2O = beta-D-fructose 6-phosphate + phosphate a myo-inositol phosphate + H2O = myo-inositol + phosphate Magnesium. Can also use manganese. Both FBPase and IMPase activities are inhibited by Ca(2+). In contrast to mammalian I-1-P phosphatases, is only very weakly inhibited by Li(+) (with an IC(50) of about 290 mM). kcat is 2.5 sec(-1) for IMPase activity (at 85 degrees Celsius) and 2.7 sec(-1) for FBPase activity (at 85 degrees Celsius). Homodimer. Belongs to the inositol monophosphatase superfamily. FBPase class 4 family.