Results 181 to 190 of about 104,062 (224)

Effects of melanin on tyrosine hydroxylase and phenylalanine hydroxylase

Biochimica et Biophysica Acta (BBA) - Enzymology, 1978
Melanin 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 ...
T, Nagatsu, Y, Numata(Sudo), T, Kato, K, Sugiyama, M, Akino   +4 more
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Pyrimidines as cofactors for phenylalanine hydroxylase

Biochemical and Biophysical Research Communications, 1978
Abstract 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.
S W, Bailey, J E, Ayling
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Activation of phenylalanine hydroxylase by phenylalanine

Biochimica et Biophysica Acta (BBA) - Enzymology, 1971
Abstract 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, 1978
AbstractA 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.
X O, Breakefield, C M, Castiglione, R, Halaban, J, Pawelek, R, Shiman   +4 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).
R. G. F. Cotton, H. H. M. Dahl, J. F. B. Mercer, I. Jennings, E. A. Haan, C. W. Chow, D. M. Danks, F. J. Morgan   +7 more
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Phenylalanine hydroxylase: metabolic aspects

Biochemical Society Transactions, 1985
Phenylalanine 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 ...
C I, Pogson, M A, Santana, M J, Fisher
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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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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.
A, Tourian, J, Goddard, T T, Puck
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PHENYLALANINE HYDROXYLASE ACTIVITY IN NEWBORN INFANTS

Pediatrics, 1964
One of the techniques that may be employed to expedite the diagnosis of phenylketonuria in the newborn infant is the phenylalanine load test. However, this is probably an impractical method for a routine examination but in the suspected sibling may permit rapid differentiation of an affected infant from one entirely normal.
R J, ALLEN, J C, HEFFELFINGER, R E, MASOTTI, M U, TSAU   +3 more
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Inactivation of purified phenylalanine hydroxylase by dithiothreitol

Biochemical and Biophysical Research Communications, 1992
Purified rat liver phenylalanine hydroxylase is inactivated in vitro by ascorbate and thiol compounds, dithiothreitol being the most effective inhibitor, with a second order rate constant for the inactivation of 0.066 +/- 0.002 mM-1.min-1 at 20 degrees C and pH 7.2.
A, Martínez, S, Olafsdottir, J, Haavik, T, Flatmark   +3 more
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