Bioconjugation of Meldrum's acid activated furan: A detergent compatible assay for protein quantitation.

A simple yet efficient assay for the quantitation of proteins ranging from plasma proteins to purified proteins from whole cell lysate, based on the bioconjugation reaction between protein and Meldrum's acid Activated Furan (MAF) is described. This easy to use, sensitive method is based on the conjugation of amine functionalities present on the protein with MAF to form the corresponding Donor Acceptor Stenhouse Adducts (DASAs) with characteristic absorption in the visible region. The reaction is rapid as well as reproducible and shows a proportionate increase in color change over a broad range of protein concentration. The assay was found to be sensitive up to 0.125 mg/mL concentration of the protein and was compatible with most of the commonly employed detergents and isolation protocols which makes it ideal for the estimation of protein samples containing detergents. Another striking feature of this protocol is its tolerance towards other major interference contributors such as chelating agents, reducing agents, carbohydrates and protease inhibitors.

2-dimensional analytic approach for anion differentiation with chromofluorogenic receptors.

By linking the urea moiety at the 1,8 positions of the carbazole fragment, we synthesized host systems 1, 2, and 3 having both chromogenic and fluorogenic signaling subunits. The spectral changes in both the signaling subunits could be easily analyzed via a simple 2-dimensional (2D) analytic approach described here, which enables us to differentiate the given set of anions. Structural studies are also reported.

Quinoxaline-imidazolium receptors for unique sensing of pyrophosphate and acetate by charge transfer.

[structure: see text] Quinoxaline derivatives (1-4) bearing two imidazolium moieties are found to strongly bind anions and show unique charge-transfer fluorescent responses to pyrophosphate and acetate, whereas they show excimer formation with other anions. Anion-binding studies are investigated with fluorescence and 1H NMR analysis, single-crystal X-ray analysis, and theoretical calculations.

Organic-inorganic hybrid compounds of Li with bisimidazole derivatives: Li ion binding study and topochemical properties.

The imidazole-based ligands, bis(imidazol-1-yl)methane (Bizm, 1a) and (pyrenyl)bis(imidazol-1-yl) methane (Pbizm,2a) were prepared. With LiClO4, these two compounds formed two novel organic-inorganic hybrid materials: a 3D network polymer Li(Bizm).ClO4 (1b) and a 1D chain polymer Li(Pbizm)2.ClO4 (2b). The intriguing topological and physiochemical characteristics of 1b and 2b are reported on the basis of the X-ray single-crystal structure analysis and Li ion binding studies.