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.