Aqueous salt solution of organic solvents as a media for enzymatic reactions

Babak Minofar

Department of Structure and Function of Proteins, Institute of Systems Biology and Ecology, Academy of Sciences of the Czech Republic, and Institute of Physical Biology, University of South Bohemia, Zamek 136, 37333 Nove Hrady, Czech Republic

e-mail: minofar@nh.usbe.cas.cz

The effect of some nonionizing, water-soluble organic solvents on the enzyme activity was studied both by experiments and molecular dynamics (MD)simulations. Also it has been shown that many mono or divalent cations and anions can enhance the activity of enzymes in aqueous solutions of organic solvents.^1,2 Organic solvents can have different effect of the catalytic reaction such as lowering the energy of activated complex or stabilization of enzyme in solution. Also using solution of organic solvents can improve the solubility of some reactant. For example in the case of haloalkane dihalogenase the mixture of organic solvent with water can increase the solubility of haloalkanes which have low solubility in water. In this work solvation and dynamics of some organic solvents in water have been studied by means of molecular dynamics (MD)simulations. Moreover the effect of mixture of some organic solvents such as DMSO, isopropanol and formamide on structure and dynamics of enzymes have been studied. Also it is found from MD data that in some cases solution of organic solvents prevent aggregation of some organic compound such as carotenoides in water.

1) Klibanov AM (2001) Improving enzymes by using them in organic solvents. Nature 409, 241–245.

2) Micaelo NM, Teixeira VH, Baptista AM & Soares CM (2005) Water dependent properties of cutinase in nonaqueous solvents: a computational study of enantioselectivity. Biophys J 89, 999–1008.