Berg and colleagues report on amino acid exchange across the human brain during endotoxin infusion. Lipopolysaccharide infusion induced a decrease in the ratio between branched chain amino acids and aromatic amino acids, increased unidirectional phenylalanine uptake, and increased net brain glutamine release. Cerebral proteolysis is suggested to play a role, but the question is whether this is ...

abstract background: molecular imprinting is a method for synthesizing polymers with structure-selective adsorption properties with applications such as, selectivity binding, drug delivery systems and anti-bodies. the present study aims at optimizing the preparation of molecularly imprinted polymer (mip) against l-phenylalanine, in order to increase phenylalanine-binding in enzymatic intestinal...

It is shown by competition experiments that tobacco cell lines have distinct transport systems for L-amino acids. For all tested amino acids the Lineweaver-Burk plots were diphasic indicating the presence of more than one carrier for any one amino acid. Moreover distinct transport systems for neutral, acidic and basic amino acids were kinetically characterized. Based on competition experiments ...

Amino acids applied to the mucosa evoke inhibitory reflexes in guinea-pig jejunum, but the receptors involved in sensory transduction are still unclear. One promising candidate is the extracellular calcium sensing receptor (CaSR), which is expressed by mucosal enteroendocrine cells and is preferentially activated by aromatic L-amino acids. We tested this by applying various amino acids to the m...

The pathway of aromatic amino acid biosynthesis was initiated by the enzyme DAHP synthase. In this branched biosynthetic pathway phenylalanine, tyrosine and tryptophan are produced. This enzyme was repressed and inhibited by three said end product of aromatic amino acids. The importance of this enzyme is microbial fermentation of aromatic amino acid production. The present study envisaged the i...

We report the rate of decomposition by ultraviolet photolysis of 4 simple amino acids in a ~mm-thick crystalline water ice matrix at T=100K to constrain the surviv-ability of these important organic molecules within ice lying near the surfaces of outer solar system bodies. As a specific example, we focus on Europa where subsurface liquid water or " warm ice " may be extruded onto the surface fr...

GPR142, a putative amino acid receptor, is expressed in pancreatic islets and the gastrointestinal tract, but the ligand affinity and physiological role of this receptor remain obscure. In this study, we show that in addition to L-Tryptophan, GPR142 signaling is also activated by L-Phenylalanine but not by other naturally occurring amino acids. Furthermore, we show that Tryptophan and a synthet...

Glutamine may be a conditionally essential amino acid in low-birth-weight (LBW) preterm neonates. Exogenously administered amino acids, by providing anaplerotic carbon into the tricarboxylic acid cycle, could result in greater cataplerotic efflux and glutamine de novo synthesis. The effect of dose and duration of amino acid infusion on glutamine and nitrogen (N) kinetics was examined in LBW inf...

A variety of aminoisoquinoline-5,8-quinones bearing α-amino acids moieties were synthesized from 3-methyl-4-methoxycarbonylisoquinoline-5,8-quinone and diverse l- and d-α-amino acid methyl esters. The members of the series were evaluated for their cytotoxic activity against normal and cancer cell lines by using the (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) (MTT) assay. From...