578 Drs. T. A. Henry and 8. J. M. Auld. [July 22, 
Fractional Precipitation of Yeast Juice with Alcohol. 
Attempts were made to isolate a definitely active preparation of the enzyme 
by tre Sing yeast juice with successive small quantities of alcohol and collect- 
ing the several precipitates so produced. It was found, however, that these 
precipitates exhibited, in a less degree, all the activities characteristic of yeast 
juice itself. Recourse was, therefore, had to the alcoholic precipitation of 
yeast juice which had been heated previously to 58° and subsequently filtered. 
The precipitate so obtained was washed with dilute alcohol, spread on glass, 
and dried by exposure over desiccating agents under reduced pressure. This 
preparation contained the glucosidolytic enzyme and invertase, but was free 
from endotryptase and zymase. 
As in all the previous experiments in which the action of yeast or yeast 
preparations on amygdalin was investigated, no dextrose could be found 
among the hydrolytic products, this having been decomposed by the zymase, 
it was thought worth while to investigate more fully the action of this new 
preparation on amygdalin. About 0-1 gramme was added to 20 ce. of a 
2-per-cent. solution of amygdalin in water and the mixture maintained at 40°. 
The odour of benzaldehyde became noticeable after 90 hours. The action 
was allowed to proceed for some time and then the benzaldehyde was 
extracted with ether and identified by conversion into dibenzylideneacetone. 
The presence of hydrocyanic acid among the hydrolytic products was proved 
by the application of the usual tests. To the liquid, left after removal of 
benzaldehyde, phenylhydrazine acetate was added and the mixture warmed 
at 100°. After about 20 minutes the phenylosazone which had separated was 
collected, washed, and recrystallised from alcohol. It melted at 205° A 
specimen of phenylglucosazone prepared at the same time melted at 205°. 
Identification of the Glucosidolytic Enzyme of Yeast. 
The data afforded by the results of the experiments already described are 
that the glucosidolytic enzyme of yeast hydrolyses amygdalin, salicin, 
arbutin, phaseolunatin, and mandelonitrile glucoside, but does not attack 
sinalbin, digitalin, or quercitrin. The temperature at which its activity 
is destroyed is about 70°, and it is most active at 40°. Its activity is 
inhibited by the presence of small quantities of alkalis or acids, but not 
by antiseptic agents. 
A comparatively large number of glucosidolytic enzymes have been 
described, but of those which hydrolyse glucosides containing the —CN 
group or —CNS group only the following are known :— . 
Emulsin, which decomposes amygdalin, dhurrin, phaseolunatin and 
gynocardin. 
