The human genome kinase genes

contains about 500 protein kinase genes; they constitute about 2% of all eukaryotic genes. Protein kinases are also found in bacteria and plants.

protein domain mimetic,” which targets the interaction between two proteins

The chemical activity of a kinase involves removing a phosphate group from ATP and covalently attaching it to one of three amino acids that have a free hydroxyl group.

Most kinases act on both and  others act on, and dual-specificity kinases act on all three. There are also protein kinases that phosphorylate other amino acids, including  that phosphorylate histidine residues.