Kinase



In chemistry and biochemistry, a kinase, alternatively known as a phosphotransferase, is a type of enzyme that transfers phosphate groups from high-energy donor molecules, such as ATP, to specific substrates. The process is referred to as phosphorylation, not to be confused with phosphorolysis, which is carried out by phosphorylases. Phosphorylation is the transfer of a phosphate group to a molecule, not the reverse, i.e., phosphorolysis, the transfer of a molecular moiety to a phosphate group. An enzyme that removes phosphate groups is known as a phosphatase.

Types
One of the largest groups of kinases are protein kinases, which act on and modify the activity of specific proteins. Kinases are used extensively to transmit signals and control complex processes in cells. Up to 518 different kinases have been identified in humans. The enormous diversity, as well as their role in signaling, makes them an object of study.

Various other kinases act on small molecules such as lipids, carbohydrates, amino acids, and nucleotides, either for signaling or to prime them for metabolic pathway. Kinases are often named after their substrates.