0000000000121445
AUTHOR
Claire Vidal-madjar
Structure and properties of hydroxyl radical modified nucleic acid components II. 8-Oxo-adenine and 8-oxo-2′-deoxy-adenosine
Abstract The tautomerism of the 8-oxo-adenine (8-oxo-A) and 8-oxo-2′-deoxy-adenosine (8-oxo-dA) was analysed on the basis of semiempirical, SCF ab initio and DFT density functional quantum chemistry calculations. The results of full gradient geometry optimisation of all possible 8-oxo-A and 8-oxo-dA structures lead to the conclusion that the most stable form is 8-keto-6-amino-tautomer. The second stable tautomer corresponds to 8-hydroxy-isomer. Such an order was unchanged after solvating process. In all studied solvents: water, methanol, acetone, cyclohexane the keto-tautomer proceeds the enol one. The preferred N-glycoside torsion angle corresponds to syn rotamer of 8-oxo-dA in all studied…
Optimisation of fast protein separations on non-porous silica-based strong anion exchangers
The adsorbed coating technology using various vinylpyrrolidone-vinylimidazole copolymer compositions was carried out on 1.7 μm non-porous monodisperse silica. It was shown that the retention properties and the loading capacity for bovine serum albumin (BSA) increases with the amount of vinylimidazole in the copolymer composition. The retention behavior of various proteins as a function of the salt composition in the eluent has been applied to find the optimal conditions for the synthesis of the anion-exchange stationary phase. The suitability of these supports for the fast separation of biological molecules is demonstrated. The best resolution and the highest speed in protein analysis was o…
Multivalent ion-exchange model of biopolymer chromatography for mass overload conditions
Abstract The simple model of multivalent ion-exchange biopolymer chromatography is analyzed on the basis of classical quasi-chemical temperature. The rigorous isotherm equation deduced from the stoichiometric displacement model (SDM) was used to stimulate the migration of a solute through the chromatographic column in the isocratic and gradient elution modes. The peak profiles generated for various sample sizes were compared with those obtained on the basis of a Langmuir isotherm. Peak tailing increases with the value of the exponent Z, defined as the ratio of the protein valency to the displacing counter-ion valency. For large Z the asymmetries due to the non-linearity of the isotherm are …
Study of conformational effects of recombinant interferon gamma adsorbed on a non-porous reversed-phase silica support.
Abstract Reversed-phase chromatography is a powerful method for separating recombinant interferon γ and one of its analogues differing only by a single amino acid residue. Structural differences of the proteins explain this separation ability as demonstrated from adsorption studies on a non-porous reversed-phase support. To reveal the structural differences occurring in the adsorbed state, two different and independent methods were employed. The variation of the retention with the slope of the linear gradient gave information about the molecular contact area of the protein with the support. For different experimental conditions, these data were correlated with the adsorbent capacities measu…