Temperature Coefficients of Enzymic Actmty and the Beat Destruction of Pancreatic and M&t Amylases.*

There are in the literature many references to the action of heat on enzymic processes. In general these are not specific, and where they are they deal, as a rule, with o?e isolated point such as the temperature of optimum activity or that of destruction. Not much reliance can be placed on the data given in some of the earlier work (1,2), as at that time very little was known as to the conditions for the optimum activity of enzymes. The effect of heat on enzymic activity through a wide range of temperature has been little studied. As enzymes are, in general, unstable substances, the effect of heat upon any reaction catalyzed by them is made up of a twofold effect. Euler (3) points out that a rise in temperature first accelerates the chemical velocity and second, inactivates the enzyme. Thus in plotting curves of the activity of an enzyme with increase in temperature the curve always tends to rise to a maximum. Sgrensen (4) says: “Therefore, the curve of the temperature should be Considered as if it were two entirely different curves, namely, a curve of the real temperature effect which increases in proportion to the temperature elevation, not only below but probably above the optimum temperature, and on the other side a curve of the destruction of the enzyme.” The maximum of this temperature curve varies according to the enzyme employed, the acidity, concentration of the substrate, presence of salts, type of solvent, etc. Much of the confusion arising from apparently conflicting data in the literature is due to the lack of fulfilling the conditions of bptimum activity of the enzyme,