Phosphatase

A phosphatase is an enzyme that removes a phosphate group from its substrate by hydrolysing phosphoric acid monoesters into a phosphate ion and a molecule with a free hydroxyl group (see dephosphorylation). This action is directly opposite to that of phosphorylases and kinases, which attach phosphate groups to their substrates by using energetic molecules like ATP. A common phosphatase in many organisms is alkaline phosphatase.

Phosphatases can be categorised into two main categories: Cysteine-dependent Phosphatases (CDPs) and metallo-phosphatases (which are dependent on metal ions in their active sites for activity).