On the Importance of the Support Material for Enzymatic Synthesis in Organic Media. Support Effects at Controlled Water Activity

Enzymes adsorbed or deposited on porous support materials have been succesfully used as catalysts in organic media. However, the support must be chosen with great care. The support can affect the partitioning of substrates, products and water in the reaction mixture and thereby indirectly influence the catalytic properties of the enzyme. Furthermore, the support can influence both the enzyme kinetics and the number of catalytically active enzyme molecules. The effects of the support on water partitioning in the system can be interpreted by measurements of the aquaphilicity (water attracting capacity) of the supports. Normally, high reaction rates are obtained with supports having low aquaphilicity. Even in experiments carried out at fixed enzyme hydration (fixed water activity) the support influences both the total activity of the enzyme and the relative rates of different reactions catalyzed by the same enzyme.