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Evidence from EPR spectroscopy that phosphorylation of Ser‐40 in bovine adrenal tyrosine hydroxylase facilitates the reduction of high‐spin Fe(III) under turnover conditions
Author(s) -
Andersson Kristoffer K.,
Haavik Jan,
Martinez Aurora,
Flatmark Torgeir,
Petersson Leif
Publication year - 1989
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(89)81603-5
Subject(s) - tyrosine hydroxylase , tetrahydrobiopterin , electron paramagnetic resonance , chemistry , tyrosine 3 monooxygenase , phosphorylation , tyrosine , enzyme , catecholamine , dissociation (chemistry) , turnover number , biochemistry , endocrinology , biology , cofactor , nuclear magnetic resonance , organic chemistry , physics
The tetrahydrobiopterin‐dependent iron‐enzyme tyrosine hydroxylase (TH) catalyses the rate‐limiting step in catecholamine biosynthesis. Electron paramagnetic resonance (EPR) data show that following phosphorylation of Ser‐40 by protein kinase A, the enzyme‐bound Fe(III), coordinated to catecholamines, can be reduced by 6‐methyl‐tetrahydropterin under turnover conditions. The 8‐fold increase in product formation upon phosphorylation can partly be explained by an increase in the fraction of active TH, by dissociation of the endogenous catecholamine inhibitors.