A new spectrofluorometric probe for the determination of trace amounts of CoA in injection, human serum and pig livers

Citrate analysis using capillary electrophoresis and complexation with Eu3+-tetracycline

A sensitive assay for citrate was developed. Citrate was incubated with 50 μM Eu³⁺-tetracycline and the complex separated using capillary electrophoresis utilizing post-column laser-induced luminescence detection in a sheath flow cuvette. Signal was linear with citrate concentration from 10 μM to 200 nM. Injection volumes were 320 pL. For the 200 nM sample, this corresponds to the injection of 64 amoles of citrate. Separation time was < 90 s with a total run time of 5 min. As an application the method was used to analyze citrate in agricultural and medicinal products. The method was also used to develop an assay for the enzyme citrate synthase.

New insights into coenzyme A interaction with mercury ions provided by mass spectrometric and circular dichroism spectroscopic approaches

The interaction of coenzyme A (CoA) with mercury ions was investigated using electrospray ionization mass spectrometry and circular dichroism spectroscopy. Our results indicated a 1:1 stoichiometric CoA-Hg complex at physiological pH. Furthermore, the CoA conformation considerably changed in the presence of mercury ions. In addition, a by-product of the reaction, thiocoenzyme A, was identified using mass spectrometry.

An organic/inorganic hybrid membrane as a solid "turn-on" fluorescent chemosensor for coenzyme A (CoA), cysteine (Cys), and glutathione (GSH) in aqueous media

The preparation of a fluorogenic sensory material for the detection of biomolecules is described. Strategic functionalisation and copolymerisation of a water insoluble organic sensory molecule with hydrophilic comonomers yielded a crosslinked, water-swellable, easy-to-manipulate solid system for water "dip-in" fluorogenic coenzyme A, cysteine, and glutathione detection by means of host-guest interactions. The sensory material was a membrane with gel-like behaviour, which exhibits a change in fluorescence behaviour upon swelling with a water solution of the target molecules. The membrane follows a "turn-on" pattern, which permits the titration of the abovementioned biomolecules. In this way, the water insoluble sensing motif can be exploited in aqueous media. The sensory motif within the membrane is a chemically anchored piperazinedione-derivative with a weakly bound Hg(II). The response is caused by the displacement of the cation from the membrane due to a stronger complexation with the biomolecules, thus releasing the fluorescent sensory moieties within the membrane.