Estimation of the Polarity of Stationary Phases for Gas Chromatography Based on Spectral Parameters

Journal of Applied Spectroscopy - The applicability of stationary liquid phases for gas–liquid chromatography was evaluated. The scale for quantitative one-parameter estimation of their...     

Spectrophotometric and Fluorimetric Determination of Amino Acids by Their Reaction with o-Phthalic Aldehyde in the Presence of Sulfite and Cyanide Ions

Optimum conditions were selected for the determination of amino acids by their reaction with o-phthalic aldehyde in the presence of sodium sulfite and potassium cyanide using glycine as an example. It was shown that the analytical characteristics of the proposed procedure are highly competitive with those of a widely employed procedure using 2-mercaptoethanol and that the stability of the analytical form (substituted isoindols) was much higher.     

Luciferase-streptavidin fusion proteins: Preparation and properties

We constructed plasmids encoding genes of fusion proteins of a thermostable mutant of Luciola mingrelica firefly luciferase (Luc) and streptavidin (SA) with the polyhistidine sequence (His₆) at the N- or C-terminus of the protein: SA-Luc-His₆, His₆-SA-Luc, Luc-SA-His₆. Fusion proteins were produced and purified; their composition, luciferase activity, thermal stability, bioluminescence spectra, and biotin-binding capacity were investigated. Streptavidin introduction does not affect the bioluminescence spectra, but it decreases the thermal stability twofold at 47°C. It was shown by size-exclusion chromatography that, depending on the plasmid structure, the fusion proteins were expressed as dimers, tetramers, and larger oligomers, which differ in luciferase activity and biotin-binding capacity. The His₆-SA-Luc fusion protein demonstrated the most optimal properties.     

Fluorimetric determination of amino acids and photochemical stability of their reaction products with ortho-phthalic aldehyde under irradiation by high-power pulsed laser

The opportunity of the highly sensitive determination of amino acids using the fluorescence of their derivatives that form in the reaction with aqueous solutions of ortho-phthalic aldehyde and nucleophilic agents, potassium cyanide, sodium sulfite, and N-acetyl-L-cysteine was studied as an example. The chemical stability of forming fluorescent compounds (substituted isoindoles) and their photochemical stability under the action of power pulsed laser radiation is higher, and the analytic characteristics of reagents are highly competive with a standard applied reagent for determining amino acids and a mixture ortho-phthalic aldehyde with 2-mercaptoethanol.