Background: DNA damage is one of the major consequences of radiation exposure onto the biological systems. A series of compounds including flavanoids were found to render DNA protection against radiation damage. In this study we elucidated the potential of rutin and rutin hydrate to protect plasmid DNA against damage induced by irradiation. Materials and Methods: DPPH and hydroxyl radical scave...

Human hemoglobin (Hb) and haptoglobin (Hp) exhibit an extremely high affinity for each other, and the dissociation of Hb tetramers into dimers is generally believed to be a prerequisite for complex formation. We have investigated Hp interactions with native Hb, αα, and ββ cross-linked Hb (ααXLHb and ββXLHb, respectively), and rapid kinetics of Hb ligand binding as well as the redox reactivity i...

The binding of liganded hemoglobin to haptoglobin, a plasma cr2-glycoprotein, is an irreversible and stoichiometric reaction that occurs physiologically at the micromolar concentration level. The study of the reaction between deoxyhemoglobin which does not bind haptoglobin and a haptoglobin solution saturated with carbon monoxide indicates that hemoglobin tetramer is incapable of binding haptog...

The pH dependence of binding of [TyrA14-125I]monoiodoinsulin to isolated rat adipocytes was investigated at 37 degrees C. Although the amount of tracer bound at steady state at pH 7.8 was 6 times that at pH 6.8, the fractional degradation of receptor-bound iodoinsulin remained the same. The decreased binding at acidic pH could be accounted for by a decrease in the affinity. The pH-induced chang...

It has been suggested that stochastic ows might be used to model the spread of a passive substance on the surface of a body of water. We deene a stochastic ow by the equations 0 (x) = x; ddt(x) = F (dt; t(x)); where F (t; x) is a eld of semimartingales on x 2 R d for d 2 whose local characteristics are bounded and Lipschitz. The particles are points in a bounded set X, and we ask how far the su...

With a view to explaining the structure-affinity properties of the ligands of the protein FKBP12, we characterized a binding intermediate state between this protein and a high-affinity ligand. Indeed, the nature and extent of the intermolecular contacts developed in such a species may play a role on its stability and, hence, on the overall association rate. To find the binding intermediate, a m...

The binding dynamics of the 2-aminoanthracenium cation (AH(+)) and 2-aminoanthracene (A) with cucurbit[7]uril (CB[7]) was studied using stopped-flow experiments. The kinetics was followed by measuring the fluorescence changes over time for AH(+) and A, which emit at different wavelengths. The studies at various pH values showed different mechanisms for the formation of the AH(+)@CB[7] complex, ...

The absorption and resonance Raman spectra and the azide binding kinetics of ferric horse heart myoglobin (Mb) and mini myoglobin (a chemically truncated form of horse heart Mb containing residues 32-139) have been compared. The steady-state spectra show that an additional six-coordinated low-spin form (not present in entire horse heart Mb, which is purely six-coordinated high spin) predominate...

The kinetic and steady-state properties of macroscopic mslo Ca-activated K+ currents were studied in excised patches from Xenopus oocytes. In response to voltage steps, the timecourse of both activation and deactivation, but for a brief delay in activation, could be approximated by a single exponential function over a wide range of voltages and internal Ca2+ concentrations ([Ca]i). Activation r...

By the use of the drug taxol, microtubules were assembled from tubulin that had GDP at its exchangeable nucleotide binding site. By means of dilution experiments and measurements of exchange of labeled subunits, it was determined that the rate of interchange of subunits between these microtubules and the solution is very slow: the upper limit of the dissociation rate constant was measured to be...