title: Regulatory mechanism of tyrosine hydroxylase activity.
abstract: Activity of tyrosine hydroxylase is regulated by feedback inhibition and inactivation by catecholamines, and activation by protein phosphorylation. In this article, reaction mechanisms for the conversion of tyrosine hydroxylase to an inactive/stable form by catecholamines, and activation of tyrosine hydroxylase by phosphorylation at Ser-40 are discussed. Inactivation may be induced by sub-stoichiometric amounts of catecholamines, and activation by phosphorylation of Ser-40 may require phosphorylation of three or all four subunits of a tyrosine hydroxylase molecule. Cooperative phosphorylation at Ser-40 in the subunits is also discussed.
authors.affiliation: Shiga Medical Center Research Institute, Moriyama 524-8524, Japan. fujisawa@shigamed.jp
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Fujisawa
authors.forename: Sachiko
authors.initials: S
authors.lastname: Okuno
mesh_terms: D000818:Animals; D004789:Enzyme Activation / Q000187:drug effects / Q000502:physiology; D025461:Feedback, Physiological / Q000187:drug effects / Q000502:physiology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D014446:Tyrosine 3-Monooxygenase / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism*
chemical_list: D014446:Tyrosine 3-Monooxygenase