Kinase

A kinase is an enzyme that catalyzes the transfer of phosphate groups from high-energy, phosphate-donating molecules (such as ATP) to specific substrates—a process known as phosphorylation. This modification can dramatically alter the activity, function, or localization of the substrate molecule and is a fundamental mechanism in regulating cellular processes. Kinases are central to metabolism, cell signaling, protein regulation, cellular transport, secretory processes, and many other pathways. The reversible phosphorylation of proteins by kinases (and dephosphorylation by phosphatases) acts as a molecular switch for turning proteins on or off in response to various stimuli. In humans alone there are at least 500 different kinase genes; up to 30% of all human proteins may be modified by kinase activity. Because they regulate so many critical pathways—including cell growth/division (cell cycle), apoptosis (programmed cell death), metabolism, immune responses—kinase dysfunction is implicated in numerous diseases such as cancer, diabetes, inflammatory disorders, neurodegenerative diseases etc. Many drugs have been developed targeting specific protein kinases.

Kinase inhibitors block the activity of kinases, preventing phosphorylation of target proteins.