The results may best be interpreted from a consideration of the 

 figure; it is seen that as the temperature is raised the rate of destruction 

 by acids and alkalis increases until finally at or about the temperature 

 of 60 C. distilled water itself slowly destroys invertase, and at 65 

 the destruction by water is quite rapid. It is evident that the destruc- 

 tion of invertase by hot water is due to the same cause as is its 

 destruction by acids and alkalis. The latter reactions are doubtless 

 hydrolyses of the complex enzym molecule and it is therefore to be 

 concluded that the destruction of invertase by hot water is caused by a 

 hydrolysis of the enzym. This conclusion doubtless applies to other 

 enzyms also. As far as is known this is the first evidence offered to 

 explain the cause of the well known destruction of enzyms by hot 

 water. This point of view explains why dry enzym preparations can 

 be heated without destruction to temperatures over 100 C. in case no 

 water is present; the hydrolysis does not then take place. 



THE INFLUENCE OF TEMPERATURE IN INCREASING THE RATES 



OF DESTRUCTION. 



In Table 2 the rates of destruction in the same medium at different 

 temperatures are compared, and in the last column the coefficient which 

 shows how many fold the rate increases for 10 rise in temperature is 

 recorded. Some of the very large and very small rates do not agree 

 with the general average in showing a coefficient of the value of 2 to 4, 

 but the limits of error in these cases are larger. The average value 

 of the coefficient is 3.1, which agrees with the general observation that 

 this factor for most chemical reactions varies between 2 and 4. The 

 hydrolytic destruction of invertase by acids, alkalis, and hot water 

 thus falls in with the common types of chemical reactions. 



TABLE 2. The temperature coefficient of the destruction. 



[Cir. 59] 



