C-1027 is an enediyne antitumor antibiotic composed of a chromophore with four distinct chemical moieties, including an (S)-3-chloro-4,5-dihydroxy-beta-phenylalanine moiety that is derived from l-alpha-tyrosine. SgcC4, a novel aminomutase requiring no added co-factor that catalyzes the formation of the first intermediate (S)-beta-tyrosine and subsequently SgcC1 homologous to adenylation domains...

l-Tyrosine and l-phenylalanine enter cells of Bacillus subtilis via a system of active transport that exhibits complex kinetic behavior. The specificity of the transport system was characterized both at low concentrations of transport substrate (where affinity for l-tyrosine or l-phenylalanine is high but capacity is low) and at high concentrations (where affinity is low but capacity is high). ...

In this study the effect of different protein levels on reproductive performance of Channa striatus was conducted. Snakehead juveniles (65.5±0.2 g) were randomly distributed into nine homogenous groups of 75 fish each. Three isocaloric experimental diets differing in protein levels were prepared. The experiment lasted for 8 months and gonadosomatic index, absolute fecundity, egg diameter, numbe...

This article focuses on the effect of yeast strains, vintage, and must sugar content amino-acid sparkling wines produced by traditional method. In experiment, concentrations before after secondary fermentation, depending type used (basic wine without fermented with immobilized yeast, classical Champagne yeast) (170, 190, 210 g per liter), vintage (2010 2011), were evaluated. Concentrations 20 f...

We assessed the approach of using intracellular free amino acid enrichment as precursor enrichment for calculating the fractional synthetic rate of using the stable isotope tracer incorporation technique. We assumed that the true rate of protein synthesis was reflected by the rate of tracer incorporation over time divided by the plateau enrichment in protein. Isolated human fibroblasts and myoc...

The essentiality of histidine in healthy adults is a controversial topic. To study the potential metabolic effects of a lack of exogenous histidine, four healthy adults consumed a histidine-free diet, with adequate energy and 1.0 g/(kg d) of an L-amino acid mixture for 48 d. Protein metabolism was monitored every 4 d by using indicator amino acid (L-[1-C]phenylalanine) oxidation (in four subjec...

The essentiality of histidine in healthy adults is a controversial topic. To study the potential metabolic effects of a lack of exogenous histidine, four healthy adults consumed a histidine-free diet, with adequate energy and 1.0 g/(kg. d) of an L-amino acid mixture for 48 d. Protein metabolism was monitored every 4 d by using indicator amino acid (L-[1-(13)C]phenylalanine) oxidation (in four s...

BACKGROUND The threonine requirement of human neonates who receive parenteral nutrition (PN) has not been determined experimentally. OBJECTIVE The objective was to determine the parenteral threonine requirement for human neonates by using the minimally invasive indicator amino acid oxidation technique with L-[1-(13)C]phenylalanine as the indicator amino acid. DESIGN Nine postsurgical neonat...

Phenylketonuria (PKU), an inborn error in phenylalanine metabolism, requires lifelong nutrition management with a low-phenylalanine diet, which includes a phenylalanine-free amino acid-based medical formula to provide the majority of an individual's protein needs. Compliance with this diet is often difficult for older children, adolescents, and adults with PKU. The whey protein glycomacropeptid...

A spectrophotometric recycling assay for the quantitation of L-phenylalanine (and phenylpyruvate) has previously been reported (Cooper et al., Anal. Biochem. 183, 210-214, 1989). The procedure involves the coupling of bacterial phenylalanine dehydrogenase with rat kidney cytosolic glutamine transaminase K. The latter enzyme possesses high affinity for phenylpyruvate. Recycling results in a > or...