Encapsulation of flavodoxin in reverse micelles.

The regulation of the properties of Desulfovibrio gigas flavodoxin in AOT/water/iso-octane micellar system was studied. UV-visible spectroscopic studies have shown that photoreduction of flavodoxin in the presence of EDTA leads to hydroquinone formation through the intermediate semiquinone. The [free FMN] - [bound to flavodoxin FMN] equilibrium (and hence, the amount of apoprotein) depends on redox state of FMN and on hydration degree which controls the micellar size. Thus, a new method of reversible cofactor removing under mild conditions (at low hydration degree of micelles) is suggested, accompained by isolation of apo-form of the protein.

The effect of water content and nature of organic solvent on enzyme activity in low-water media. A quantitative description.

A simple theoretical model was suggested to describe quantitatively the effect of water content and nature of organic solvents on catalytic behavior of enzymes suspended in low-water media. The model was based on a generally accepted notion that the destruction of the protein hydration shell is one of the main reasons for protein denaturation by organic solvents. The validity of the model was confirmed by the example of catalytic behavior of immobilized laccase suspended in water/organic mixtures of different compositions. In addition, the results were used to demonstrate that the effect of organic solvents and/or water content on catalytic behavior of enzymes in low-water media can be adequately assessed only in terms of the full kinetic description based on properly determined Vm and Km values.