
1905.] On the Probable Existence of Emulsin in Yeast. 577 
58°, and 65°. These temperatures differ somewhat from those given by 
Wroblewski, being on the whole a few degrees higher, but agreement in this 
respect is scarcely to be expected in experiments of this kind, since the 
formation of the various precipitates is probably due to the coagulation in 
turn of different proteid matters, including the enzymes, and the temperatures 
at which the coagulates are formed probably depends to some extent on the 
concentration of the various proteids in the yeast juice, and these, in turn, 
will vary with the previous history of the yeast from which the juice is 
prepared. The results obtained in one set of these experiments are shown in 
the following table :— 
Temperature | Activity of filtrate towards— 

fy lies pees Change observed. 
juice was heating. | 
heated. | Glucose. | Amygdalin. 
degrees. minutes. 
4) 90 INONG ) 2.16.0 <isnamiectaeebe aha Active. «s..c6.%. Active 
42 20 None 
46 18 Turbidity 
| 48 25 Voluminous precipitate...) Slight ......... Benzaldehyde formed 
after 47 hours 
50 20 INOHG 4.050. Sec inditencasaeene INOHIG! ics s:2300 5 aes Active 
53 40 Slight flocculence 
55 30 Voluminous precipitate...| oe Benzaldehyde formed 
after 45 hours 
56 20 None 
58 30 Voluminous precipitate... ae Benzaldehyde formed 
; after 34 hours 
63 15 Turbidity 
66 25 Voluminous precipitate... site Benzaldehyde formed 
after 58 hours 
70 20 INONG, A ienrmse eee ecete dete cce a Benzaldehyde formed 
after several days 
70—72 20 ING), casee sivetbolaungaee sees a No action 



It was observed in all the sets of heat coagulation experiments that the 
activity of the yeast juice towards amygdalin increased as each of the first 
few coagulates was removed. This increase in activity is no doubt due in part 
to the gradual concentration of the glucosidolytic enzyme in the liquid as the 
result of continued heating, but it may also be due in part to the removal of 
other enzymes, especially the endotryptase which, as has been shown, appears 
to gradually destroy the glucosidolytic enzyme. The maximum activity of 
the juice towards amygdalin is reached when it has been heated at 58° 
(according to Hahn and Geret* the endotryptase is destroyed when the yeast 
juice is heated at 60°), further heating diminishes the activity, which finally 
disappears at about 70°. Yeast juice which has been heated to 70° still 
hydrolyses sucrose and must, therefore, contain invertase. 
7 LOC. Get. 
