Handbook of Solvents - George Wypych - ChemTech - Ventech!

14.4.3 Choice of solvent for enzymatic reaction 879
Table 14.4.3.3. Effect of the solvent on enantioselectivity of lipase PS. [Adapted, by
permission, from D. Bianchi, A. Bosetti, P. Cesti and P. Golini, Tetrahedron Lett., 33,
3233(1992)].
Solvent logP ε Nucleophile E
H2O 78.54 H2O 17
hexane 3.5 1.89 n-propanol 146
CCl4 3.0 2.24 n-propanol 502
toluene 2.5 2.37 n-propanol 120
iso-propyl ether 1.9 3.88 n-propanol 152
2-methyl-2-butanol 1.45 5.82 n-propanol 589
2-methyl-2-butanol 1.45 5.82 H2O 63
n-propanol 0.28 20.1 n-propanol 181
acetonitrile -0.33 36.2 n-propanol 82
1,4-dioxane -1.1 2.2 n-propanol 164
As mentioned above, no correlation was reported in a large number of articles on the
effects of solvents on the enzyme specificity/selectivity, although correlations between the
specificity/selectivity and physico-chemical properties of the solvents were successful in
some combinations of an enzymatic reaction for a set of solvents. Therefore, attempts to rationalize
the phenomena based on either physico-chemical properties of the solvents or on
their structure, are at present clearly unsatisfactory from the point of view of predictable
value. Further experiments carried out under more strictly defined condition are necessary
to reach the quantitative explanation of the whole phenomena.
14.4.3.5 Concluding remarks
Activity, stability, and selectivity of an enzyme are affected considerably by nature of organic
solvents as well as free water content in the enzyme-catalyzed reaction in the organic
solvents. However, rational criteria for the selection of a proper solvent among vast variety
of the organic solvents are very limited so far. Researchers are obliged to resort to empirical
approach by examining some kinds of solvent for the enzyme-catalyzed reaction concerned
at the present state of art.
References
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