Regulation of recombinant rat tyrosine hydroxylase by dopamine.

Tyrosine hydroxylase and regulation of dopamine synthesis.

Tyrosine hydroxylase is the rate-limiting enzyme of catecholamine biosynthesis; it uses tetrahydrobiopterin and molecular oxygen to convert tyrosine to DOPA. Its amino terminal 150 amino acids comprise a domain whose structure is involved in regulating the enzyme's activity. Modes of regulation include phosphorylation by multiple kinases at four different serine residues, and dephosphorylation ...

Presynaptic regulation of tyrosine hydroxylase activity in rat striatal synaptosomes by dopamine analogs.

Regulation of Dopamine @-Hydroxylase in Rat Adrenal Glands

Rat adrenal gland levels of dopamine &hydroxylase are subject to dual control. Activation of the splanchnic nerves to the adrenal medulla by reserpine induces the synthesis of dopamine /3-hydroxylase without altering the rate of enzyme degradation. In contrast, hypophysectomy causes a decline in steady state dopamine fi-hydroxylase levels by first accelerating the rate of degradation, then by s...

Regulation of tyrosine hydroxylase activity by muscarinic agonists in rat adrenal medulla.

Regulation of tyrosine hydroxylase (TH) enzymatic activity in vivo by muscarinic receptor agonists in rat adrenal medulla was characterized in this study. Bethanechol and carbachol produce dose-dependent increases in rat adrenal TH activity. These increases are maximal (approximately 3-fold) using 10 mg/kg bethanechol or 0. 5 mg/kg carbachol and are totally inhibited by prior administration of ...

Inactivation of phosphorylated rat tyrosine hydroxylase by ascorbate in vitro.

Tyrosine hydroxylase activity is reversibly controlled by the actions of several protein kinases. Previous studies showed that, following phosphorylation by protein kinase A, physiological concentrations of ascorbate irreversibly inactivate tyrosine hydroxylase. Several studies were performed to establish the mechanism of inactivation. We found that inactivation occurred under oxygen-free condi...