1910.] 



Studies on Enzyme Action. 



363 



of amygdalin is primarily conditioned by amygdalase and that any j8-glucase 

 which it contains cannot operate until the digliicoside is resolved into Fischer's 

 glucoside and glucose, the inactivity of the Phaseolus enzyme towards amygdalin 

 may be ascribed to the absence from it of all but traces of amygdalase. From 

 this point of view, Fischer's glucoside, salicin and methyl-/3-giucoside, rather 

 than amygdalin, are to be compared with the Phaseolus glucoside and are 

 the appropriate test materials to use in determining whether the correlated 

 enzyme belongs to the ^ class, whether indeed it may not be simple /3-glucase 

 but present in considerably smaller proportion than in emulsin. 



Our observations show that methyl-yS-glucoside is far less readily attacked 

 by the Phaseolus enzyme than it is by alniond-emulsin. It is well known 

 that this glucoside is somewhat rapidly attacked by emulsin ; that phaseo- 

 lunatase acts on it only slowly is shown by the following figures derived 

 from an experiment made with an M/5 solution containing 50 c.c. of the 

 enzyme extract per 100 c.c. : — 





1 



day. 



2 



days. 



days. 



9 



days. 



15 

 days. 



17 

 days. 



33 

 days. 





2 -3 



7-2 



26 1 



30-5 



40-6 



43-7 



51 -5 



In the case of salicin, on the other hand, the disproportion in the rates of 

 change appears to be far less marked. 



To ascertain the behaviour of the three cyanophoric glucosides, experiments 

 were made as follows : six solutions were prepared: — 



(1) By mixing 15 c.c. of a 4M/10 amygdalin solution with 15 c.c. of a 

 dilute solution (1 : 10) of emulsin. 



(2) By mixing 15 c.c. of a 4M/10 amygdalin solution with 15 c.c. of the 

 solution of phaseolunatase. 



(3) By mixing 15 c.c. of a 4M/10 Fischer's glucoside solution with 15 c.c. 

 of the dilute solution -of emulsin. 



(4) By mixing 15 c.c. of a 4M/10 Fischer's glucoside solution with 15 c.c. 

 of the phaseolunatase solution. 



(5) By mixing 15 c.c. of a 4M/10 solution of phaseolunatin with 15 c.c. 

 of a strong solution of emulsin. 



(6) By mixing 15 c.c. of a 4M/10 solution of phaseolunatin with 15 c.c. 

 of phaseolunatase solution. 



These were kept at 37°. The same solution of enzyme was used in the case 

 of all three glucosides, except that the emulsin used with phaseolunatin was 

 ten times as strong as that used in the other cases. After 24 hours the 



