This paper is aimed to estimate the transmittance of electronic effects in fluorescein molecule between phthalic acid residue and xanthene moiety. Despite almost orthogonal orientation latter with respect rest molecule, some influence substituents this 9-aryl ring on dissociation hydroxyl group hydroxyxanthene cannot be ruled out. In order reveal (possible) effect, we blocked carboxylic via est...

The biophysical properties of a tryptophan-shifted mutant of phosphofructokinase from Bacillus stearothermophilus (BsPFK) have been examined. The mutant, designated W179Y/Y164W, has kinetic and thermodynamic properties similar to the wild-type enzyme. A 2-fold decrease in kcat is observed, and the mutant displays a 3-fold smaller K(0.5) for the substrate, fructose-6-phosphate (Fru-6-P), as comp...

In this paper we report on the charging behavior of latex particles in aqueous suspensions. We use static light scattering and acid-base titrations as complementary techniques to observe both effective and bare particle charges. Acid-base titrations’at various ionic strengths provide the pH dependent charging curves. The surface chemical parameters (dissociation constant of the acidic carboxyli...

When we use Scatchard analysis for insulin receptor on intact cells, internalization of insulin may affect the Scatchard analysis. In this study, results from Scatchard analysis for insulin receptor on hepatocytes of streptozotocin (STZ)-induced diabetic rats were compared with those from association and dissociation studies and those from Scatchard analysis using hepatocyte membrane which does...

Anilinonaphthalenesulfonate (ANS) and tryptophan compete for binding to the trp repressor protein; thus, the fluorescence decrease associated with ANS dissociation can be used as a fluorometric marker for tryptophan binding to the protein. Using this approach, the tryptophan equilibrium dissociation constant was measured at 25 degrees C to be 3.7 (+/- 1.2) X 10(-5) M, a value which compares fav...