Current formulations for acute tryptophan (Trp) or tyrosine (Tyr) plus phenylalanine (Phe) depletion and loading cause undesirable decreases in ratios of Trp or Tyr + Phe to competing amino acids (CAA), thus undermining the specificities of these tests. Branched-chain amino acids (BCAA) cause these unintended decreases, and lowering their content in a new balanced control formulation in the pre...

Surface-enhanced Raman scattering (SERS) spectra were measured for monolayers of various amino acids: L-methionine (Met), L-cysteine (Cys), L-glycine (Gly), L-leucine (Leu), L-phenylalanine (Phe), and L-proline (Pro) and their homodipeptides (Met-Met, Cys-Cys, Gly-Gly, Leu-Leu, Phe-Phe, and Pro-Pro) deposited onto a colloidal gold surface. Orientation of amino acids and their homodipeptides, as...

We employ a particular form of two-dimensional infrared four-wave mixing (2DIR FWM) as a vibrational spectroscopic tool to quantify the amino acid content of a number of peptides. Vibrational features corresponding to ring modes of the aromatic groups of phenylalanine (Phe) and tyrosine (Tyr), as well as a methylene mode that is used as an internal reference, are identified. We show that the ra...

The fragmentation behavior of deprotonated L-phenylalanine (Phe) and its homologues including L-homophenylalanine (HPA) and L-phenylglycine (PG) was investigated using collision-induced dissociation mass spectrometry coupled with a negative ion atmospheric pressure corona discharge ionization (APCDI) technique. The deprotonated molecules [M-H](-) fragmented to lose unique neutral species, e.g.,...

Phenylketonuria (PKU) is a disease of the catabolism phenylalanine (Phe), caused by an impaired function enzyme hydroxylase. Therapeutics based on restriction Phe intake, which mostly requires modification diet. Dietary restrictions can lead to imbalances in specific nutrients, including lipids. In present study, plasma phospholipidome PKU and healthy children (CT) was analyzed hydrophilic inte...

Liquid-liquid equilibrium (LLE) occurs at a subzero temperature for the acetonitrilewater binary system.When the equilibrium temperature is below its LLE critical temperature of 1.32 C, the top phase is acetonitrile-rich and the bottom phase water-rich. It was observed that a human growth hormone analog with 191 amino acids partitioned exclusively into the bottom phase and its bioactivity was r...

The site-selective chemical diversification of biomolecules constitutes an unmet challenge capital importance within medicinal chemistry and biology. functionalization otherwise unreactive C?H bonds holds great promise for reducing the reliance on existing functional groups, thereby streamlining syntheses. Over last years, a myriad peptide labelling techniques featuring metal-catalyzed reaction...

OBJECTIVE STR/ORT mice provide a well-known model for murine idiopathic OA, with histological joint lesions resembling those of human OA. This model was used to investigate protective effects of the dipeptide aspartyl-phenylalanine-1-methyl ester (Asp-Phe-OMe or aspartame) via the oral route vs a regular diet. METHODS STR/ORT mice were housed individually and fed diets with or without Asp-Phe...

BACKGROUND/AIMS Dietary proteins have potent eating-inhibitory and glucose-lowering effects, which may be mediated via effects of amino acids on gastrointestinal hormone and motor function, although little information is available. We have now evaluated the effects of L-phenylalanine (L-Phe) and L-glutamine (L-Gln) on antropyloroduodenal motility and plasma cholecystokinin (CCK) concen-trations...