Moderate doses of glucagon (20 micrograms/kg I.V.) are sufficient to stimulate rat hepatic phenylalanine hydroxylase in vivo. In addition, the stimulation of the tetrahydrobiopterin-dependent phenylalanine hydroxylase activity in livers of animals fed on a high-protein diet has been correlated with an elevated phosphate content. The tetrahydrobiopterin-dependent hydroxylase activity in these an...

A sensitive method was developed for determining the phenylalanine hydroxylase activity of crude tissue preparations in the presence of optimum concentrations of the 6,7-dimethyl-5,6,7,8-tetrahydropterin cofactor (with ascorbate or dithiothreitol to maintain its reduced state) and substrate. Tissue distribution studies showed that, in addition to the liver, the kidney also contains significant ...

Specific mutations in the gene encoding phenylalanine hydroxylase (PAH), located on chromosome 12q22-24.1, are linked to tetrahydrobiopterin (BH4; sapropterin)-responsive phenylketonuria (PKU). Diagnosis is usually done through the newborn screening for PKU, followed by a BH4 loading test. So far, more than 60 mutant alleles, presenting with a substantial residual PAH activity (average approxim...

Mammalian phenylalanine hydroxylase (PAH) catalyses the conversion of L-phenylalanine to L-tyrosine in the presence of dioxygen and tetrahydrobiopterin; it is a highly regulated enzyme. Little is known about the rates of synthesis and degradation of PAH in vivo. The enzyme has been reported to have a half-life of approx. 2 days in rat liver and 7-8 h in rat hepatoma cells, but the mechanism of ...

Abstract Objective Phenylketonuria (PKU) is caused by a specific mutation of the phenylalanine hydroxylase (PAH) gene. The deficiency PAH results in high levels (Phe), low tyrosine (Tyr), and reduced catecholamine neurotransmitters. majority PKU patients, if untreated, develop severe mental retardation. contribution Phe Tyr retardation largely unknown. In this study, we used organic hippocampal...

In the present study we report on the identification of ten novel mutations in the phenylalanine hydroxylase (PAH) gene of Brazilian patients with phenylketonuria (PKU): IVS5-54A>G, IVS6+17G>T, E205A, F240S, K274E, I318T, L321L, C357G, IVS11+17G>A and S411X. These mutations were detected during the characterization of the PAH genotypes of 115 patients with PKU from the southeast region of Brazi...

Phenylketonuria (PKU) is an inborn error of amino acid metabolism with an autosomal recessive inheritance caused in most cases by mutations in the phenylalanine hydroxylase (PAH) gene. PKU has wide allelic heterogeneity. Here we report a novel heterozygous substitution (c.1223G>T (p.Arg408Leu)) in the PAH gene in an Iranian PKU family. The patient was 19-yr-old female with diagnosis of moderate...

Phenylketonuria (PKU) is a metabolic disorder whereby phenylalanine metabolism deficient due to allelic variations in the gene for hydroxylase ( PAH ). There no cure PKU other than orthotopic liver transplantation, and standard of care patients limited dietary restrictions key amino acid supplementation. Therefore, Pah was edited pig fibroblasts generation clone piglets that harbor common sever...