Results 201 to 210 of about 16,453 (233)

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
openaire   +3 more sources

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
openaire   +3 more sources

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
openaire   +3 more sources

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
openaire   +3 more sources

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
openaire   +3 more sources

A simple radioisotope assay for phenylalanine hydroxylase

Analytical Biochemistry, 1967
Abstract An isotopic assay for phenylalanine hydroxylase activity has been devised. The assay involves incubation of the enzyme with p -tritio- l -phenylalanine followed by the addition of N -iodosuccinimide to iodinate the tyrosine produced. The tritium released by this combination appears as tritiated water and is proportional to the amount of ...
Amnon Abramowitz, Gordon Guroff
openaire   +3 more sources

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.
Torgeir Flatmark, Jan Haavik, Sigridur Olafsdottir, Aurora Martinez   +3 more
openaire   +3 more sources

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
openaire   +3 more sources

Hepatic Phenylalanine Hydroxylase and PKU

1975
The conversion of phenylalanine to tyrosine in mammalian tissues is catalyzed by a complex enzyme system composed of several essential enzymes and cofactors. All of these components have been assayed in liver biopsy samples from patients with the classic form of PKU.
openaire   +2 more sources

Phenylalanine Hydroxylase Activity-Reply

Archives of Pediatrics & Adolescent Medicine, 1983
In Reply .—For most metabolic disorders, a diagnosis based on a single symptom would not be acceptable. Hyperphenylalaninemia is a symptom that in a newborn infant suggests either complete or partial PH deficiency (PKU), dihydropteridine reductase deficiency, or deficiency in biopterin synthesis.
openaire   +2 more sources