CHAPTER VII 



INVERTASE AND MALTASE 



Invertase. — Invertase, or sucrase, is the enzyme which 

 brings about the inversion of cane sugar according to the 

 following equation : — 



Cane sugar Dextrose Lsevulose 



Invertase is most readily prepared from beer yeast. A 

 quantity, say ten grams, is thoroughly washed with water 

 with the aid of a filter pump ; it is then mixed with 100 c.c. 

 of water and about 1 c.c. of chloroform ; the chloroform 

 prevents the growth of the yeast. On warming the mixture 

 for a few houxs at about 30° C. and filtering, a solution is 

 obtained which contains the enzyme invertase. This can be 

 proved by adding, say, 5 c.c. of the solution to 50 c.c. of a 

 10 per cent, solution cane sugar and warming to about 30° C. 

 for an hour. Before testing for the presence of invert sugar, 

 the solution should be boiled to remove the chloroform present, 

 which otherwise would tend to reduce the FehUng solution. 

 The boiled solution should be cooled and made up to its 

 original volume with distilled water, and the invert sugar 

 determined by means of Fehling solution and by the polari- 

 meter in the usual way. 



It wUl be seen that the separation of invertase from the 

 yeast has not necessitated the breaking up of the yeast cell ; 

 simple diffusion has been sufficient to extract it. Invertase 



