How do kinases work?

Kinases catalyze the transfer of a phosphate group from ATP or GTP to specific target molecules. This process is known as phosphorylation, which is crucial in processes such as cell division, cell signaling, and gene expression. There are 3 basic steps kinases follow in their mechanism. The first step is the recognition of the substrate. The kinase recognizes and binds to the specific protein substrate molecule which can be an enzyme, a surface receptor, or another protein domain. This is carried out by the interactions between the kinase’s active site and the amino acid residues on the substrate. The second step is the transfer of the phosphate group. When the substrate becomes bound, the kinases transfer a phosphate group from ATP or GTP to a specific amino acid residue on the substrate molecule, typically a serine, threonine, or tyrosine residue. This transfer is assisted by the catalytic residues within the kinase active site. Additionally in this step, ATP is hydrolyzed to ADP and Pi. The third step is the release of the phosphorylated product. Once the phosphate group has been transferred, the phosphorylated product is then released from the kinase active site. Now, the kinase can bind to another substrate molecule in order to repeat the process.