Kinase is a type of enzyme that transfers phosphate groups from high-energy donor molecules to specific substrates, a process referred to as phosphorylation. Kinases are part of the larger family of phosphotransferases. Kinases are not to be confused with phosphorylases, which catalyze the addition of inorganic phosphate groups to an acceptor, or with phosphatases, which remove phosphate groups. The phosphorylation state of a molecule, whether it be a protein, lipid, or carbohydrate, can affect its activity, reactivity, and its ability to bind other molecules. Therefore, kinases are critical in metabolism, cell signaling, protein regulation, cellular transport, secretory processes, and countless other cellular pathways.