title: Phosphorylation and activation of tryptophan hydroxylase by exogenous protein kinase A.
abstract: The catalytic subunit of protein kinase A increases brain tryptophan hydroxylase activity. The activation is manifested as an increase in Vmax without alterations in the Km for either tetrahydrobiopterin or tryptophan. The activation of tryptophan hydroxylase by protein kinase A is dependent on ATP and an intact kinase and is inhibited specifically by protein kinase A inhibitors. Protein kinase A also catalyzes the phosphorylation of tryptophan hydroxylase. The extent to which tryptophan hydroxylase is phosphorylated by protein kinase A is dependent on the amount of kinase used and is closely related to the degree to which the hydroxylase is activated. These results suggest that a direct relationship exists between phosphorylation and activation of tryptophan hydroxylase by protein kinase A.
authors.affiliation: Department of Psychiatry and Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, Michigan, USA.
authors.forename: P A
authors.initials: PA
authors.lastname: Johansen
authors.forename: I
authors.initials: I
authors.lastname: Jennings
authors.forename: R G
authors.initials: RG
authors.lastname: Cotton
authors.forename: D M
authors.initials: DM
authors.lastname: Kuhn
mesh_terms: D000818:Animals; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D004789:Enzyme Activation; D008297:Male; D009994:Osmolar Concentration; D010766:Phosphorylation; D047428:Protein Kinase Inhibitors; D051381:Rats; D017207:Rats, Sprague-Dawley; D013681:Tegmentum Mesencephali / Q000201:enzymology; D014365:Tryptophan Hydroxylase / Q000378:metabolism*
chemical_list: D047428:Protein Kinase Inhibitors; D014365:Tryptophan Hydroxylase; D017868:Cyclic AMP-Dependent Protein Kinases