Activation of enzymes in organic media at low water activity by polyols and saccharides.

Horse liver alcohol dehydrogenase and alpha-chymotrypsin were deposited on a porous support material, Celite. After equilibration at a well-defined water activity, the catalytic activity was measured with diisopropyl ether as reaction medium. The effects of the presence of polyols and simple saccharides in the preparations were investigated. The additives caused a considerable increase in the amount of water bound to the preparation at a fixed water activity. At low water activities the catalytic activity was increased and at high water activity it was decreased by the additives. The presence of additives increased the ratio of alcoholysis-to-hydrolysis activity of chymotrypsin.