alpha-chymotrypsin and diisopropyl-ether

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.

Topics: Alcohol Dehydrogenase; Animals; Catalysis; Cattle; Chymotrypsin; Enzyme Activation; Enzymes, Immobilized; Ethers; Horses; Monosaccharides; Solvents; Sugar Alcohols; Water

alpha-Chymotrypsin was adsorbed on solid support materials and the catalytic activity of the preparations in organic solvents was studied. The activity was highly dependent on the nature of the support material and on the amount of water present in the reaction mixture. There appears to be competition for the water in the system between the enzyme, the support material and the solvent. The support materials were characterized by measuring their ability to absorb water from water-saturated diisopropyl ether. For the quotient: (amount of water on the support)/(amount of water in the solvent) in the model system the term aquaphilicity was proposed. The activity of adsorbed chymotrypsin in diisopropyl ether decreased with increasing aquaphilicity of the support material. The same trend was observed when the activity of horse liver alcohol dehydrogenase adsorbed on different supports was measured in diisopropyl ether.

Topics: Acetonitriles; Adsorption; Alcohol Dehydrogenase; Animals; Catalysis; Cattle; Chromatography, Gas; Chymotrypsin; Enzymes; Ethers; Horses; Liver; Pancreas; Solubility; Solvents; Water