Anomalous temperature dependence of the activity of immobilized alpha-chymotrypsin preparations

Catalytic activity of alpha-chymotrypsin preparations covalently included in the matrix of the poly-N-isopropylacrylamide gel does not follow Arrhenius equation above the low critical temperature of the polymer dissolution. Starting from this temperature, at which the changes of polymer structure takes place (hydrophobization), the temperature increase results in a rate lowering for the chemical reaction catalyzed by the enzyme. This phenomenon is reversible. A correlation between temperature dependence of the immobilized alpha-chymotrypsin activity and the dehydration degree of the carrier is observed. The decrease of the water content in the matrix causes a change of the substrate specificity of the immobilized alpha-chymotrypsin.     

The temperature dependence of the mechanical properties of porous iron

Conclusions It has been shown that the general character of change in strength and plasticity of porous iron between room temperature and 400° is similar to the change in these characteristics for ordinary nonporous iron. The analogy in the change in properties is more clearly expressed in specimens with low values of porosity (3–30% for the ultimate strength, and 3–19% for the relative elongation). For higher values of porosity the properties change monotonically.