Lactobacillus casei 393 cells which were energized with glucose (pH 6.0) took up glutamine, asparagine, glutamate, aspartate, leucine, and phenylalanine. Little or no uptake of several essential amino acids (valine, isoleucine, arginine, cysteine, tyrosine, and tryptophan) was observed. Inhibition studies indicated that there were at least five amino acid carriers, for glutamine, asparagine, gl...

Pheochromocytoma tyrosine hydroxylase was reported to have unusual catalytic properties, which might be unique to the tumor enzyme (Dix, T. A., Kuhn, D. M., and Benkovic, S. J. (1987) Biochemistry 24, 3354-3361). Two such properties, namely the apparent inability to hydroxylate phenylalanine and an unprecedented reactivity with hydrogen peroxide were investigated further in the present study. T...

L-3,4-Dihydroxyphenylalanine (L-DOPA) is a known allelochemical exuded from the roots of velvet bean (Mucuna pruriens L. Fabaceae). In the current work, we analyzed the effects of L-DOPA on the growth, the activities of phenylalanine ammonia-lyase (PAL), tyrosine ammonia-lyase (TAL), and peroxidase (POD), and the contents of phenylalanine, tyrosine, and lignin in maize (Zea mays) roots. Three-d...

This paper reports the blood-borne mammary tumor virus activity of C3H/Crgl female virgin mice previously fed phenylalanine-deficient diets. Whole blood was removed from three groups of female virgin C3H/Crgl mice previously fed semipurified diets containing, respectively, 0.075, 0.120, and 0.300% phenylalanine for 8 months. The blood was twice diluted and 0.3 ml was injected into each C3HfBALB...

Branched chain amino acids (BCAA) are particularly effective anabolic agents. Recent in vitro studies suggest that amino acids, particularly leucine, activate a signaling pathway that enhances messenger ribonucleic acid translation and protein synthesis. The physiological relevance of these findings to normal human physiology is uncertain. We examined the effects of BCAA on the phosphorylation ...

The enzyme phenylalanine hydroxylase (EC 1.14.16.1) catalyses the hydroxylation of phenylalanine to tyrosine in man and other mammals. The hepatic enzyme is controlled by a reversible phosphorylation mechanism [l]. The phosphorylation state of the enzyme is under hormonal control. For example, glucagon stimulates phosphorylation and activation of the enzyme through the action of the cyclic AMP-...

Antiarrhythmics, anticonvulsants, and local anesthetics target voltage-gated sodium channels, decreasing excitability of nerve and muscle cells. Channel inhibition by members of this family of cationic, hydrophobic drugs relies on the presence of highly conserved aromatic residues in the pore-lining S6 segment of the fourth homologous domain of the channel. We tested whether channel inhibition ...

Pancytopenia in childhood can be caused by a variety of underlying diseases including hematological and non-hematological entities. Phenylketonuria (PKU) is an inborn error of phenylalanine metabolism. No association between PKU and pancytopenia has ever been reported. We report the first case of PKU revealed by a pancytopenia at presentation. The patient was an infant girl born to healthy non-...

Newborn screening for phenylketonuria (PKU) started with Robert Guthrie (1916–1995) who developed the bacterial inhibition test for the semiquantitative analysis of phenylalanine, which was the first test suitable for high throughput analysis. In addition, he introduced the ‘Guthrie filter card’ as a transport medium for dried blood which is still used today. Realizing the potential of his appr...