[2] In enzymology, the term serine/threonine protein kinase describes a class of enzymes in the family of transferases, that transfer phosphates to the oxygen atom of a serine or threonine side chain in proteins.

Protein phosphorylation in particular plays a significant role in a wide range of cellular processes and is a very important post-translational modification.

The systematic name of this enzyme class is ATP:protein phosphotransferase (non-specific).

Since the consensus sequence residues of a target substrate only make contact with several key amino acids within the catalytic cleft of the kinase (usually through hydrophobic forces and ionic bonds), a kinase is usually not specific to a single substrate, but instead can phosphorylate a whole "substrate family" which share common recognition sequences.

[14] Limited benefit of serine/threonine kinase inhibitors has been demonstrated in ovarian cancer[15] but studies are ongoing to evaluate their safety and efficacy.