364 Prof. H. E. Armstrong and Mr, E. Horton. [Mar. 3, 



amount of hydrolysis effected was determined in each case by estimating the 

 amount of hydrogen cyanide liberated. 





Solution (30 c.c.) containing 



Hydrolyst. 



3 -0676 grammes 

 amygdalin. 



1 -7709 grammes 

 Fischer's glucoside. 



1 -4828 grammes 

 phaseolunatin. 





Weight 

 hydrolysed. 



Percentage 

 hydrolysed. 



Weight 

 hydrolysed. 



Percentage 

 hydrolysed. 



Weight 

 hydrolysed. 



Percentage 

 hydrolysed. 



Emulsin, 



2-162 



70 -5 



1 -655 



93 -5 







5 hours 















Emulsin, 



2-5 



81 -5 



1 -595 



*89-5 



0-052 



3-5 



24 hours 















Phaseolunatase, 



0-107 



3-5 



1 -533 



86 -0 



1 -334 



90 -0 



24 hours 















* The lower percentage in this instance is to be accounted for by loss of hydrogen cyanide on 

 removal of the 5-hour sample. Whilst no appreciable loss occurs at 25° through the removal of 

 samples at intervals, this is not the case at the higher temperature. 



The striking fact brought out by these experiments is the manner in which 

 the Phaseolus enzyme acts equally well on Fischer's glucoside and phaseo- 

 lunatin, although it has but little action on amygdalin. On tlie assumption 

 that emulsin is relatively rich in /3-glucase — far more so than the Phaseolus 

 enzyme — and that both glucosides are of the yS-type because of this similar 

 behaviour, it is difficult to understand tlie inactivity of emulsin towards 

 phaseolunatin. It is to be noted that our observations do not stand alone : 

 Dunstan and his co-workers came to the conclusion that emulsin has no action 

 on phaseolunatin. 



It would seem that there are peculiarities either in the enzymes or in the 

 glucosides which await discovery. That the Phaseolus enzyme should not 

 act on amygdc'din is not surprising, as it may well be destitute of amygdalase ; 

 it is, liowever, difficult to ex))lain the inactivity of alinoiid-emulsin towards 

 phaseolunatin, in view of the activity of phaseolunatase towards Fischer's 

 glucoside as well as towards phaseolunatin ; such a result is scarcely in favour 

 of the view that the activity of emulsin as a hydrolyst of /^-glucosides is due 

 to a 8imi)le /S-glucase, i.e. an enzyme compatible with and iiiHuenced by 

 glucose alone. 



As bearing on this issue, the following ex[)erim(Mits were made with pressed 

 yeast juice kindly placed at our disposal by Dr. Harden : four solutions were 

 prepared : — 



