Protein kinase active site

The **kinase active site** is a highly conserved region within all protein kinases, comprising the primary catalytic machinery for transferring the γ-phosphate from ATP to an acceptor amino acid (serine, threonine, or tyrosine) on substrate proteins[1][4][6][7]. The active site is formed at the interface of the kinase N-lobe (five-stranded β-sheet, αC-helix, glycine-rich loop) and C-lobe (primarily α-helical with catalytic and activation loops), and contains conserved sequence motifs including the HRD and DFG motifs[1][4][7]. Essential to catalysis, the active site facilitates ATP and magnesium binding, aligns the substrate, and mediates phosphoryl transfer[1][4][5]. Many drugs are designed to fit this pocket, competitively inhibiting ATP binding and thus blocking kinase activity. The term "kinase active site" does not refer to a single protein or drug target but is instead a functional term used to describe the conserved enzymatic site within members of the vast kinase enzyme family[1][4]. Therefore, it should not be used as a canonical drug target. **Note:** - The term "kinase active site" is *not* a proper molecular target; it refers generically to a functional region found in all protein kinases, not to a unique protein or gene product. Drugs and studies should reference the specific kinase (e.g., "BCR-ABL kinase," "Protein kinase C alpha," "EGFR kinase") targeted, not the generic "kinase active site."[1][4] - All functions, disease roles, and drugs provided are features of this structural region across multiple (often hundreds of) individual kinases, not of a single molecule.

Other names

Kinase active siteProtein kinase catalytic site

ATP-competitive inhibition (drug blocks ATP binding); Substrate-competitive inhibition; Allosteric inhibition (binding near or within active site, altering conformation)