In enzymology, a [tyrosine 3-monooxygenase] kinase (EC 2.7.11.6) is an enzyme that catalyzes the chemical reaction

ATP + [tyrosine-3-monooxygenase] ${\displaystyle \rightleftharpoons }$ ADP + phospho-[tyrosine-3-monooxygenase]

Thus, the two substrates of this enzyme are ATP and tyrosine 3-monooxygenase, whereas its two products are ADP and phospho-(tyrosine-3-monooxygenase).

This enzyme belongs to the family of transferases, specifically those transferring a phosphate group to the sidechain oxygen atom of serine or threonine residues in proteins (protein-serine/threonine kinases). The systematic name of this enzyme class is ATP:[tyrosine-3-monoxygenase] phosphotransferase. Other names in common use include pheochromocytoma tyrosine hydroxylase-associated kinase, STK4, and tyrosine 3-monooxygenase kinase (phosphorylating). This enzyme participates in MAPK signaling pathway and non-small cell lung cancer.

• Pigeon D, Drissi-Daoudi R, Gros F, Thibault J (1986). "[Copurification of tyrosine hydroxylase from rat pheochromocytoma by protein kinase]". Comptes Rendus de l'Académie des Sciences, Série III. 302 (12): 435–8. PMID 2872947.
• Pigeon D, Ferrara P, Gros F, Thibault J (1987). "Rat pheochromocytoma tyrosine hydroxylase is phosphorylated on serine 40 by an associated protein kinase". J. Biol. Chem. 262 (13): 6155–8. PMID 2883182.