1904] 



Studies on Enzyme Action. 



193 



adopted consists in mixing 5 c.c. of water at 100, containing 

 0'5 gramme of sodium acetate, with the 5 c.c. withdrawn, then 

 shaking with charcoal and filtering through a double filter. 



Table X. 



To effect a direct comparison of the activity of maltase towards 

 maltose and a-methyl glucoside, the two substances were hydrolysed 

 by the same yeast extract under precisely similar conditions. The 

 extract used in this case was prepared by digesting 5 grammes of 

 dried yeast with 100 c.c. of water at 22 during 1 hour. 



Table XL 



It will be seen that the maltose was hydrolysed very much more 

 quickly than the a-methyl glucoside. In both cases the velocity 

 coefficient K diminishes as action proceeds ; but to a far greater extent 

 in the case of maltose. This difference is obviously due to the 

 different influence exercised by the products of change in the two 

 cases. It is to be remembered that two molecules of glucose are pro- 

 duced by the hydrolysis of maltose but only one from a-methyl 

 glucoside ; any retardation, therefore, which glucose can effect should 

 be less obvious in the case of the glucoside. 



