L-Tyrosine (Tyr) is an aromatic amino acid synthesized de novo in plants and microbes. In animals, Tyr must be obtained through their diet or synthesized from L-phenylalanine. In addition to protein synthesis, Tyr serves as the precursor of neurotransmitters (e.g., dopamine and epinephrine) in animals and of numerous plant natural products, which serve essential functions in both plants and hum...

Phenylalanine ammonia-lyase (PAL) links the plant primary and secondary metabolisms, its product, trans-cinnamic acid, is derived into thousands of diverse phenylpropanoids. Bambusa oldhamii BoPAL4 has broad substrate specificity using L-phenylalanine, L-tyrosine, L-3,4-dihydroxy phenylalanine (L-DOPA) as substrates to yield p-coumaric caffeic respectively. The optimum reaction pH for three was...

Trans-cinnamic acid and p-coumaric are valuable intermediates in the synthesis of flavonoids widely employed food, flavor pharmaceutical industries. These products can be produced by deamination L-phenylalanine L-tyrosine catalyzed phenylalanine ammonia lyase or tyrosine lyase. Phenylalanine ammonia-lyase (PAL, EC 4.3.1.5) from Rhodotorula glutinis do not exhibit strong substrate specificity co...

In this study, silver nanoparticles were chemically synthesized and deposited on glass substrates using a reducing agent of sucrose, at 50°C. Different characterizations including atomic force microscopy (AFM), field emission scanning electron microscopy (FESEM), and Raman spectroscopy were obtained to study silvery substrates. Then, the silvery substrates were used as the SERS substrates to de...

conclusions this finding may help improve early detection, differential diagnosis, genetic counseling, and even treatment of patients with pku. introduction phenylketonuria (pku) is an autosomal recessive inborn error of phenylalanine metabolism, which is caused by mutation in phenylalanine hydroxylase (pah) gene. most of the pah mutations are missense mutations (67%), which are followed by sma...

950 CLINICAL CHEMISTRY, Vol. 41, No. 6, 1995 creasing concentrations of these amino acids were analyzed (data not shown). These results suggest that Tyr and Leu in serum are measured as Phe to various degrees by the PDH preparations examined here. The increased utilization of Tyr and Leu by the Sigma and Biocatalysts preparations of PDH accounts for the positive biases obtained with these PDH s...

Somatotropin (ST) treatment promotes animal growth and allows for the conservation of amino acids by increasing nitrogen retention and reducing ureagenesis and amino acid oxidation. To determine whether the improvement in amino acid conservation with ST treatment involves regulation of urea cycle enzyme activities in both liver and intestine, growing swine were treated with either ST (150 micro...