In enzymology, a phosphatase (EC 3.1.3.17) is an enzyme that catalyzes the chemical reaction In enzymology, a phosphatase (EC 3.1.3.17) is an enzyme that catalyzes the chemical reaction Thus, the two substrates of this enzyme are phosphorylase a and H2O, whereas its two products are phosphorylase b and phosphate. This enzyme belongs to the family of hydrolases, specifically those acting on phosphoric monoester bonds. The systematic name of this enzyme class is phosphohydrolase. Other names in common use include PR-enzyme, phosphorylase a phosphatase, glycogen phosphorylase phosphatase, protein phosphatase C, and type 1 protein phosphatase.