Chemometric Comparison of Thin-Layer Chromatography,Gradient High-Performance Liquid Chromatography,and Computational Methods for Lipophilicity Assessment of Model Compounds

JPC – Journal of Planar Chromatography – Modern TLC - Thin-layer chromatography (TLC) on two adsorbents (RP18 and CN) and with six modifiers (acetonitrile, acetone, dioxane, propan...     

The Role of Lipids in Allosteric Modulation of Dopamine D2 Receptor—In Silico Study

The dopamine D₂ receptor, belonging to the class A G protein-coupled receptors (GPCRs), is an important drug target for several diseases, including schizophrenia and Parkinson’s disease. The D₂ receptor can be activated by the natural neurotransmitter dopamine or by synthetic ligands, which in both cases leads to the receptor coupling with a G protein. In addition to receptor modulation by orthosteric or allosteric ligands, it has been shown that lipids may affect the behaviour of membrane proteins. We constructed a model of a D₂ receptor with a long intracellular loop (ICL3) coupled with G_iα1 or G_iα2 proteins, embedded in a complex asymmetric membrane, and simulated it in complex with positive, negative or neutral allosteric ligands. In this study, we focused on the influence of ligand binding and G protein coupling on the membrane–receptor interactions. We show that there is a noticeable interplay between the cell membrane, G proteins, D₂ receptor and its modulators.     

Optimization of the extraction conditions of amino acid dabsyl derivatives

Summary Moist buffered paper chromatography is proposed for the selection of the optimum conditions for the extraction of dabsyl derivatives of amino acids. It is shown for each individual acid and optimum pH value exists at which the distribution coefficient reaches a maximum. The optimum pH values can be easily determined from chromatographic data. The linear correlation between the static distribution coefficients and the R_M values permit the direct calculation of the distribution coefficient from the chromatographic data.     

Quantitative determination of trace amounts of L-alanine in triglycine sulphate crystals by HPLC

Summary A method for the quantitative determination of L-alanine in triglycine sulphate crystals, in the presence of excess amounts of glycine, is described. L-alanine is determined after derivatization with 4-N,N-dimethyl-aminoazobenzene-4-sulfonyl chloride (DABS-Cl) and in the presence of DABS-valine used as the internal standard. The results obtained indicate that the method permits the determination of alanine in triglycine sulphate crystals at concentrations of about 1%.