Prevention of the denaturation of enzymes is frequently indispensable to their technological application. This is exemplified by the following five operational factors of importance in the practical use of enzymes: 1. Enzymes isolated from their in Vivo environment usually become labile, and their lifetime sometimes does not exceed minutes (1–4). For example, the stability of immobilized aspartase proved insufficient for technological use of this enzyme (5). 2. For many processes, elevated temperature is desirable. The rates of chemical reactions, including enzymatic, increase with temperature; so that at higher temperatures, the required conversion of the substrate will be achieved in a shorter time or with a smaller amount of immobilized enzyme. This is very important for technological processes where the cost of the enzyme is a limiting factor, e. g., glucoamylase (6). Also, higher temperatures allow germ-free conditions to be maintained (7), which are indispensable for, say, the food industry (8,9). On the other hand, denaturation of biocatalysts intensifies (1–3) at elevated temperatures. 3. Reaction equilibrium may be such that the required products are obtained only if the reaction is carried out in an aqueous-organic mixture with a high proportion of the organic component. Under such conditions enzymes as a rule lose their catalytic activity or specificity (2,10; see also references in 11). 4. Sometimes the pH optimum of an enzymatic reaction and the pH range within which the enzyme is stable do not coincide. A good example is synthesis of penicillin antibiotics under the action of penicillin amidase; equilibrium in the synthesis is shifted toward the product in an acidic medium, where the enzyme is rather unstable (12). 5. It may not be convenient to use an enzyme immediately upon harvesting or isolation. Hence there is a need for stabilization against inactivation during prolonged storage (13).