1907.] 



Studies on Enzyme Action. 



357 



Table VI. — Action of an Extract of Top Yeast prepared at 25° before and 

 after Heating at Higher Temperatures. 



Glucoside used. 



Treatment of extract. 



Amount hydrolysed at 25°. 



24 hours. 



48 hours. 



120 hours. 



Amygdalin •< 



Cane-sugar < 



Methyl-a-glucoside ...< 



Unheated 



per cent. 

 10-5 



7-8 



o-o 



100-0 



100-0 



54-2 



40-2 

 1-7 



o-o 



per cent. 

 17-9 

 17-9 



o-o 



100-0 



100-0 



86-8 



51-4 

 3-2 



o-o 



per cent, 

 racemised 



100-0 



o-o 



Heated at 50° (1 hour) 

 „ 60° „ 



Unheated 



Heated at 50° (1 hour) 



„ 60° „ 



Unheated 



Heated at 50° (1 hour) 

 „ 60° „ 



Table VII. — Action of an Extract of Top Yeast prepared at 25° before and 



after Heating at 60° during 1 hour. 



Glucoside used. 



Treatment of extract. 



Amount hydrolysed at 25° in 

 52 hours. 





f Unheated 



per cent. 

 27-5 



o-o 

 o-o 



96-6 

 100-0 

 100-0 



o-o 



< Heated at 60° 





L „ 60° and acidified* ... 



("Unheated, diluted to 1 in 50 ... 

 < Heated at 60° 





[_ Heated at 60° and acidified 



Heated at 60° and acidified 





* The extract which had been heated at 60° became sufficiently alkaline to convert amygdalin 

 into isoamygdalin after a long period of digestion (Table YI). N/1000 acetic acid does not 

 condition any measurable amount of hydrolysis. The expression "acidified" in the table is to be 

 interpreted as meaning that acetic acid was added in the proportion of 0*001 gramme -molecule per 

 litre of extract. 



Hydrolysis of Methyl-u-G-Iucoside. — It will be observed on reference to the 

 tables, that methyl-a-glucoside is always more or less attacked so long as 

 amygdalin is acted upon, but that a very marked diminution in activity 

 towards this glucoside attends the disappearance of the maltase (Tables IV 

 and V). The inference that the methyl-a-glucoside is attacked by the two 

 enzymes maltase and " amygdalase " cannot well be disputed — it is clearly 

 necessary to assume that either an a-glucase exists together with amygdalase, 





