A method was developed to study the unsupplemented phenylalanine hydroxylase system in rat liver slices. All of the components of the systemtetrahydrobiopterin, dihydropteridine reductase, and the hydroxylase itself-are present under conditions which should be representative of the actual physiological state of the animal. The properties of the system in liver slices have been compared to those...

A method was developed to study the unsupplemented phenylalanine hydroxylase system in rat liver slices. All of the components of the system--tetrahydrobiopterin, dihydropteridine reductase, and the hydroxylase itself--are present under conditions which should be representative of the actual physiological state of the animal. The properties of the system in liver slices have been compared to th...

We have found that the induction of phenylalanine hydroxylase by hydrocortisone and serum in confluent cultures of H4-II-E-C3 rat hepatoma cells is accompanied by an increase in polysomal mRNA specific for phenylalanine hydroxylase, as measured by translation in a cell-free protein-synthesizing system. Thus, the induction is mediated largely, if not entirely, by a pretranslational mechanism, po...

A method was developed to study the unsupplemented phenylalanine hydroxylase system in rat liver slices. All of the components of the systemtetrahydrobiopterin, dihydropteridine reductase, and the hydroxylase itself-are present under conditions which should be representative of the actual physiological state of the animal. The properties of the system in liver slices have been compared to those...

The adrenergic amines noradrenaline and adrenaline increased flux through phenylalanine hydroxylase by approx. 50%. This effect, which appears to be mediated by an alpha-adrenergic mechanism, was accompanied by a rapid increase in the phosphorylation of phenylalanine hydroxylase. Although ionophore A23187 mimicked the effects of the adrenergic amines, vasopressin was completely without effect o...

Friend mouse erythroleukemia cells do not synthesize detectable levels of phenylalanine hydroxylase [phenylalanine 4-monooxygenase; L-phenylalanine, tetrahydropteridine:oxygen oxidoreductase (4-hydroxylating), EC 1.14.16.1] and hence are unable to grow in medium totally lacking tyrosine. These cells were fused with the cytoplasts of rat hepatoma cells that synthesize phenylalanine hydroxylase c...

phenylketonuria (pku) is one of the most common metabolic inborn diseases caused by mutations in the phenylalanine hydroxylase (pah) gene. this gene is linked to a variable number of tandem repeats (vntr) region which is a polymorphic marker that facilitates the implementation of prenatal diagnosis and carrier screening. in this study, vntr with 13 repeats that has not been reported previously ...