A kinase is a type of enzyme that catalyses the addition of a phosphate (PO43-) group to a molecule, through a process known as phosphorylation. This occurs where by a high-energy phosphate-donating molecule such as ATP is dephosphorylated, providing the phosphate group to add to a molecule, producing a new phosphorylated molecule and energy. Because the phosphoanhydride bond contains a high level of energy, kinases are required to stabilise the reaction, in addition to increasing the rate of reaction through orientating the phosphate group and substrate correctly.
Kinases are heavily involved in cell communication, mediating signal transduction cascades through the addition and removal of phosphate groups activating or inhibiting molecules. Due to their potential to release energy through the release of a phosphate group and their involvement in cell signalling processes, kinases are present throughout the body, making kinases key targets in drug design. Due to the anti-inflammatory properties and the potential of kinases in cancer treatments, kinases and kinase-inhibitors are now the subject of extensive medical research.