Reduction of nitrates,the no donors,by hemoglobin in the presence of cysteine

Hemoglobin (Hb) reduces 3,3-bis(nitroxymethyl)oxetane (NMO) only in the presence of cysteine (Cys) via intermediate cysteine thionitrate. The kinetics of the reaction of NMO with Cys and the kinetics and mechanism of formation of NO in the ternary system Hb-NMO-Cys were studied. The formation rate of Hb-NO in the ternary system is higher than that of Hb-NO in the reaction of Hb only with NO ₂ ⁻ generated in the binary system NMO-Cys. The second-order rate constants of the main reaction steps in the system Hb-NMO-Cys were estimated by simulating the kinetics of the reactions with a system of equations taking into account equilibria between all components of the reaction mixture. Hemoglobin reduces cysteine thionitrate, the intermediate in the reaction of NMO with Cys, to NO. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 725–731, April, 2007.     

Polarity of Thymine and 6-Methyluracil-Modified Porous Polymers,According to Data from Inverse Gas Chromatography

Russian Journal of Physical Chemistry A - The affinity of surfaces of porous polymer Polysorb-1 samples modified with thymine (5-methyluracil) and 6-methyluracil toward sorbates capable of various...     

Separating Enantiomers of Haloalkanes and Alcohols on a Stationary Phase Based on the Supramolecular Structure of Melamine with Induced Chirality

Russian Journal of Physical Chemistry A - A new chiral stationary phase is proposed that is based on the supramolecular structure of melamine self-assembled in the mode of the induction of...     

Improving the Selectivity of the Determination of Organophosphorus Insecticides and Carbamates by Enzyme Assay

Enzyme assay is proposed for improving the selectivity of the determination of an organophosphorus (carbamate) insecticide in the presence of a heavy-metal salt in a sample (exemplified by a model system containing proserine and mercuric bromide). The method involves the use of a substrate–indicator system based on acylthiocholine and Ellman's reagent (or its derivative).     

Solvation Excess of Urea over Water in Humic Acid in Three-Component Solutions Saturated with the Biopolymer

Humic acids were extracted from brown coals of the Kara-Keche deposit (Kyrgyzstan) and characterized. The solubility of humic acid in aqueous urea solutions was studied. The solvation excess of urea over water on humic acid in solution was calculated. The possibility of simultaneous binding of urea molecules on three independent centers of humic acids was shown. An estimation of humic acid molecular dimensions in aqueous urea solutions is given.     

Complex Formation of Dimethylaminomethylcalix[4]resorcinarene and 2-Dimethylaminomethylphenol with Cu(II) Salicylaldiminates

Electronic and ESR spectroscopy was used to show that the reactions of dimethylaminomethylcalix[4]resorcinarene with Cu(II) salicylaldiminates bearing alkyl substituents at the salicylaldiminate nitrogen atom give 1 : 1 adducts with the dimethylamino group coordinated axially to the Cu(II) complex. The spatially organized calix[4]resorcinarene structure and the possibility of outer-sphere interactions favor a much higher stability of the adduct compared with the similar complex with 2-dimethylaminomethylphenol. In going from alkyl to aryl substituents, salicylaldiminates are replaced by the anion derived from dimethylaminomethylcalix[4]resocinarene. The same replacement takes place in the reaction with 2-dimethylaminomethylphenol.     

Features of vortex formation under the impact of a pressure pulse on a gas region bounded by the foam layer

The features of the dynamic processes related to the interaction between air shock waves and aqueous foam barriers accompanied by formation of vortex flows are simulated numerically and investigated. The method of solving is based on the two-phase gas-liquid mixture model generalized for solving spatial problems with the use of the equations of state in the analytic form which describe the thermodynamic properties of the mixture components.