Abstract
An alcohol dehydrogenase from the hyperthermophilic archaeon Aeropyrum pernix was activated by water-immiscible organic solvents. This activation was influenced by the kind and the concentration of the added organic solvents. Vmax was increased more than ten times, when the mole fraction of acetonitrile was 0.1. This effect was large when the organic solvents with the large log P value were added. In fact, Vmax showed a strong positive correlation with the log P value of the mixed solvent at the same mole fraction of water, while it was not affected by the kind of organic solvents added. The activation energy was decreased with the increase of the log P value of the solvent. This means that increasing of the log P value is more effective in lower temperature. Consequently, increasing of the log P value by organic solvents is a useful method to use thermophilic enzymes, which are less active at room temperature.
