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Pyrimidines as cofactors for phenylalanine hydroxylase
Biochemical and Biophysical Research Communications, 1978Abstract It has been generally assumed that a tetrahydropterin (2-amino-5,6,7,8-tetrahydro-4-pteridinone) is essential for activity of the three aromatic amino acid hydroxylases. In this report it is shown that appropriately substituted pyrimidines can assume the role of cofactor for phenylalanine hydroxylase.
J.E. Ayling, S.W. Bailey
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Effects of melanin on tyrosine hydroxylase and phenylalanine hydroxylase
Biochimica et Biophysica Acta (BBA) - Enzymology, 1978Melanin inhibited rat liver phenylalanine hydroxylase, but activated tyrosine hydroxylase from rat brain (caudate nucleus), rat adrenal glands, and bovine adrenal medulla. Activation of tyrosine hydroxylase by melanin was demonstrated with the extensively dialyzed enzyme and in suboptimal concentrations of the substrate (tyrosine) and the cofactor (6 ...
Kenji Sugiyama +4 more
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Activation of phenylalanine hydroxylase by phenylalanine
Biochimica et Biophysica Acta (BBA) - Enzymology, 1971Abstract 1. 1. Phenylalanine activates phenylalanine hydroxylase ( l -phenylalanine, tetrahydropteridine:oxygen oxidoreductase (4-hydroxylating), EC 1.14.3.1), when dithiothreitol is used to regenerate 2-amino-4-hydroxy-6,7-dimethyltetrahydropteridine. 2. 2.
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Phenylalanine hydroxylase in melanoma cells
Journal of Cellular Physiology, 1978AbstractA pigmented subclone of Cloudman S91 melanoma cells, PS1‐wild type, can grow in medium lacking tyrosine. This ability is conferred by phenylalanine hydroxylase activity, and not by tryptophan hydroxylase, tyrosine hydroxylase or tyrosinase activities, although the latter activity is also present in these cells.
John M. Pawelek +4 more
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Phenylalanine hydroxylase: metabolic aspects
Biochemical Society Transactions, 1985Phenylalanine hydroxylase [L-phenylalanine,tetrahydropteridine :oxygen oxidoreductase (4-hydroxylating); EC 1.14.16.11 catalyses the first reaction in the irreversible catabolism of the essential amino acid phenylalanine. Studies of the isolated enzyme and of phenylalanine metabolism in viuo and in oitro support the view that the hydroxylase plays the ...
M. Angelica Santana +2 more
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Mechanism of action of phenylalanine hydroxylase
Biochemistry, 1981The oxidation of 6-methyltetrahydropterin and tetrahydrobiopterin coupled to the formation of tyrosine by phenylalanine hydroxylase generates a precursor species to the quinonoid product that is tentatively identified as a 4a-hydroxy adduct based on its spectral similarity to the 4a-hydroxy-6-methyl-5-deazatetrahydropterin.
Stephen J. Benkovic +3 more
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Molecular Biology of Phenylalanine Hydroxylase
Journal of Inherited Metabolic Disease, 1986Phenylalanine hydroxylase (PH; EC 1.14.16.1) is a complex enzyme with three substrates and three activators. Little is known about the structural features which are necessary for the function of this enzyme; only the phosphorylation site is known (Wretburn et al., 1980).
F. J. Morgan +7 more
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Treatment of phenylalanine hydroxylase deficiency
Acta Paediatrica, 1994In phenylalanine hydroxylase deficiency detected by screening treatment in early life, both age at start of treatment and phenylalanine control during treatment are the major determinants of eventual psychological status. The influence of phenylalanine control declines with age but executive performance is influenced by hyperphenylalaninaemia at all ...
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Unresponsiveness to tetrahydrobiopterin of phenylalanine hydroxylase deficiency
Metabolism, 2010Conflicting results have been reported concerning the efficacy of tetrahydrobiopterin (BH4), the cofactor of phenylalanine hydroxylase, for reducing phenylalanine (Phe) concentration in phenylketonuria (PKU). We aimed to test quantitatively the effects of BH4 in PKU patients.
Ponzone A +5 more
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