Results 241 to 250 of about 32,654 (265)

Mechanism of action of phenylalanine hydroxylase

Biochemistry, 1981
The 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, D. E. Wallick, Robert F. Dietrich, Robert A. Lazarus   +3 more
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Molecular Biology of Phenylalanine Hydroxylase

Journal of Inherited Metabolic Disease, 1986
Phenylalanine 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, H. H. M. Dahl, Chung Wo Chow, E. A. Haan, J. F. B. Mercer, David M. Danks, I. Jennings, R. G. F. Cotton   +7 more
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Unresponsiveness to tetrahydrobiopterin of phenylalanine hydroxylase deficiency

Metabolism, 2010
Conflicting 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, PORTA, FRANCESCO, MUSSA, ALESSANDRO, ALLUTO, Alessandra, FERRARIS, SILVIO, SPADA, MARCO   +5 more
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Treatment of phenylalanine hydroxylase deficiency

Acta Paediatrica, 1994
In 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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Hepatic phenylalanine hydroxylase activity in hyperphenylalaninaemia

Journal of Inherited Metabolic Disease, 1981
AbstractPhenylalanine tolerancein vivo has been compared with the phenylalanine hydroxylase activity of liver biopsy specimens in 14 newly detected cases of hyperphenylalaninaemia. Hepatic phenylalanine hydroxylase activity does not predict the degree of dietary restriction that will be required.
J. L. Dhondt, J. P. Farriaux
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Phenylalanine Hydroxylase from Human Kidney

Enzyme, 1975
In this report the presence, and level, of phenylalanine hydroxylase in the cortex of human kidney is established. The average activity found in 15 surgically removed kidneys was 47.2 plus or minus 11.2 mU/g wet weight of tissue. The average value, determined under the same experimental conditions, for two human liver biopsies was 217 mU/g tissue.
G D Helfand, J E Ayling, W D Pirson
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Connecting Mutant Phenylalanine Hydroxylase With Phenylketonuria

Journal of Clinical Monitoring and Computing, 2008
The building of a quantitative relationship between genotype and phenotype would be great helpful for better clinical monitoring, diagnosis, prognosis and treatment. As the phenylketonuria is an autosomal recessive disorder caused by mutations in the phenylalanine hydroxylase, in this study we build a descriptively quantitative relationship between ...
Shaomin Yan, Guang Wu
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Phenylalanine hydroxylase in dilute lethal mice

Biochimica et Biophysica Acta (BBA) - General Subjects, 1973
Abstract The steady-state specific activity of hepatic phenylalanine hydroxylase in the 19–20-day-old dilute lethal mouse d 1 / d 1 is 2-fold higher than in its wild-type control D / D . The apparent K m values for phenylalanine and tetrahyfropteridine are identical for mutant and control enzymes.
Treiman, D M, Tourian, A
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Electrostatic Activation of Rat Phenylalanine Hydroxylase

Biochemical and Biophysical Research Communications, 1994
The conversion of phenylalanine to tyrosine is accelerated approximately five fold by phosphorylation of the enzyme which catalyzes this step, phenylalanine hydroxylase. To gain a clearer understanding of the mechanism of this activation, we have applied site-directed mutagenesis to specifically modify a clone of the hydroxylase at the phosphorylation ...
Bruce A. Citron, Seymour Kaufman, Michael Davis   +2 more
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Phenylalanine hydroxylase activity in mammalian cells

Journal of Cellular Physiology, 1969
AbstractSurvey of twelve mouse tissues revealed the presence of appreciable phenylalanine hydroxylase activity in the pancreas and kidney as well as the liver but in no other of the tissues tested. Single cell suspensions of mouse liver were prepared by use of tetraphenylboron.
Judy M. Goddard, Ara Tourian, Theodore T. Puck   +2 more
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