title: Inositol phospholipids cause the activation of adrenal tyrosine hydroxylase through their electrostatic action on the enzyme.
abstract: The effects of inositol phospholipids on adrenal tyrosine hydroxylase (TH) were studied. Phosphatidylinositol (PI), phosphatidylinositol 4-phosphate (PIP) and phosphatidylinositol 4,5-bisphosphate (PIP2) caused a rapid and concentration-dependent activation of TH in vitro. The potency of this activation was dependent on the number of phosphate groups in the lipid molecule, and the activation was completely suppressed by increasing the concentrations of salts in the reaction mixture. These results seem to indicate that the activation of TH by inositol phospholipids may be due to their electrostatic action, and suggest a possible involvement of inositol phospholipids in the regulation of TH activity in vivo.
mesh_terms: D000313:Adrenal Medulla / Q000201:enzymology; D000818:Animals; D002417:Cattle; D004789:Enzyme Activation; D007700:Kinetics; D019269:Phosphatidylinositol 4,5-Diphosphate; D018129:Phosphatidylinositol Phosphates; D010716:Phosphatidylinositols / Q000494:pharmacology*; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism*
chemical_list: D019269:Phosphatidylinositol 4,5-Diphosphate; D018129:Phosphatidylinositol Phosphates; D010716:Phosphatidylinositols; C037178:phosphatidylinositol 4-phosphate; D014446:Tyrosine 3-Monooxygenase