Phenylketonuria (PKU) is the most common autosomal recessive disorder of amino acid metabolism. Thedisease is caused mainly by mutations in the phenylalanine hydroxylase (PAH) gene, encoding phenylalaninehydroxylase (PAH) enzyme. The PAH enzyme deficiency results in the elevation of phenylalanine inthe blood, which may cause severe irreversible mental retardation in the affect...

The role of hyperthermia during regional alkylating agent chemotherapy is controversial. The aim of this study was to determine the exact contribution of hyperthermia to tumor response during isolated limb infusion with l-phenylalanine mustard. Rats bearing rodent fibrosarcoma on the hindlimb underwent isolated limb infusion with saline, saline plus heat, l-phenylalanine mustard, l-phenylalanin...

Calculation of rates of protein synthesis, based upon incorporation of [14C]phenylalanine into protein, depended upon use of the specific activity of phenylalanyl-tRNA. At a perfusate phenylalanine concentration of 0.01 mM, the specific activity of phenylalanyl-tRNA was 65 and 155% of extracellular and intracellular specific activities, respectively. At this concentration, the rate of protein s...

Considerable evidence supports the view (1) that the primary metabolic lesion in phenylketonuria is a block in the conversion of phenylalanine to tyrosine due to the absence of a labile protein component of the liver hydroxylating system (2). However, the mechanism by which this metabolic defect in liver is translated into the mental retardation which clinically characterizes this disease is un...

An amino acid-incorporating system has been obtained from ungerminated wheat embryos. This system has very low endogenous activity, but phenylalanine incorporation can be stimulated by the addition of polyuridylic acid. The poly U-stimulated system is similar to those from other sources in that it requires ribosomal particles, supernatant fluid, soluble ribonucleic acid, adenosine triphosphate,...

The early steps in the biosynthesis of the aromatic amino acids in microorganisms leading to the formation of alicyclic precursors are rather well known (1, 2). Information regarding the regulation of these steps is beginning to accumulate (3, 4). A considerable gap, however, still exists in our knowledge about the properties and the regulation of the enzymes involved in the final aromatization...

Phenylalanine dehydrogenase (L-phenylalanine:NAD oxidoreductase, deaminating; EC 1.4.1.-) was found in various thermophilic actinomycetes. We purified the enzyme to homogeneity from Thermoactinomyces intermedius IFO 14230 by heat treatment and by Red Sepharose 4B, DEAE-Toyopearl, Sepharose CL-4B, and Sephadex G-100 chromatographies with a 13% yield. The relative molecular weight of the native e...

A bifunctional protein denoted as the P protein and encoded by pheA is widely present in purple gram-negative bacteria. This P protein carries catalytic domains that specify chorismate mutase (CM-P) and prephenate dehydratase. The instability of a recombinant plasmid carrying a pheA insert cloned from Erwinia herbicola resulted in a loss of 260 bp plus the TAA stop codon from the 3' terminus of...