and Tompson a have shown that cane sugar protects invertase from 

 destruction by hot water, and it is well known that diastase is not 

 so easily destroyed by hot water if maltose is in the solution; it is 

 then an analogous fact that cane sugar protects invertase from the 

 action of alcohol. The most plausible explanation is that these 

 sugars combine with the enzym, and the resulting compound is not 

 so easily attacked by alcohol or hot water. In Circular No. 59 

 further data are presented on this interesting subject. 



THEORY OF THE BATE OF INVERSION OF CANE SUGAR DURING 

 THE DESTRUCTION OF THE INVERTASE. 



The rate of inversion of cane sugar by invertase in dilute solution 

 follows the unimolecular order and it has just been shown that the 

 rate of destruction by alcohol does the same. If invertase is added 

 to a solution of cane sugar in aqueous alcohol of a strength which 

 destroys the enzym, there occur two simultaneous reactions, the 

 inversion of the cane sugar and the destruction of the invertase. 

 The theory of these dependent or coupled reactions is as follows: 

 At constant temperature start with a solution containing A gram 

 molecules of cane sugar per liter and 7 units of invertase. After 

 the lapse of t minutes let there be in the solution i units of invertase 

 and (A - x) gram molecules of cane sugar. The rate of destruction 

 of the invertase is 



-2}-*,* ---- CD 



in which ~k 2 is the velocity-coefficient of the destruction reaction. 

 The integral of Equation 1 under the condition that i=7 when t = is 



i = Ie-** .... (2) 

 The rate of inversion of the cane sugar is 



^ = ^ (A-x^lc, (A-x)e-** .... (3) 



where Ic 1 is the velocity-coefficient of the inversion when 7 units of 

 invertase are present. The integral of Equation 3 under the condi- 

 tion that x = when t = is 



Equation 4 has been used in finding the velocity of inversion of 

 cane sugar by invertase (&J in 50 per cent alcohol. A mixture of 600 

 cc of 0.2 normal cane sugar solution in 55 per cent alcohol (which 

 was also 0.02 normal with respect to acetic acid) with 60 cc of 

 dialized invertase solution was kept at 30 C. and the progress of the 

 inversion measured polarimetrically from time to time, the samples 

 being made alkaline before each reading of the rotation. In Table 5 



o J. Chem. Soc., 1890, 67:900. 

 [Cir. 58] 



