Catalyzes strongly the dephosphorylation of fructose-1-phosphate (Fru1P) and slightly the dephosphorylation of 6-phosphogluconate (6P-Glu). It has low beta-phosphoglucomutase activity. Magnesium. Can also use other divalent metal cations as manganese, cobalt or zinc. Optimum pH is between 6 and 7.5. Belongs to the HAD-like hydrolase superfamily. CbbY/CbbZ/Gph/YieH family.