1908. | Studies on Enzyme Action. 323 
Eventually, however, we succeeded in determining both hydrogen cyanide 
and glucose in a fairly satisfactory manner, although not with the degree of 
accuracy we desired. | 
The results of such determinations having shown that apparently the 
production of glucose was in advance of the production of hydrogen cyanide 
to a not inconsiderable extent during the earlier part of the change, it 
appeared probable that the action of emulsin was comparable with that of 
acids and that Fischer’s glucoside was the main initial product of change: 
we therefore endeavoured to isolate this substance when the action was about 
half complete. 
The neutral solution was carefully evaporated on the water bath and the 
syrup ultimately obtained was then extracted with ethylic acetate in the 
manner described by Caldwell and Courtauld.* The ultimate product was 
identical in crystallographic character, melting point and solubility with 
Fischer’s glucoside and the melting point of a mixture of the two substances 
was that of the glucoside ; it also gave an acetate indistinguishable from that 
prepared from Fischer’s glucoside. 
There can, therefore, be practically no doubt that besides gluco-lactase, 
emulsin contains a (-glucase capable of hydrolysing substances such as 
8-methylglucoside, together with a third enzyme, amygdalase. That gluco- 
lactase is present in addition. to amygdalase is proved by the fact that the 
former may be destroyed by heating, whilst the latter persists. 
In view of this result, we are justified in laying emphasis on the statement 
made in No. X of these studies:—‘ As the investigation is extended, the 
evidence becomes more and more convincing that the action which an 
enzyme exercises is specific ; in other words, that it is limited to compounds 
of a particular type—to a greater extent, indeed, than is recognised in earlier 
communications of this series.” In fact, it is difficult to overrate the value 
of enzymes as diagnostic agents. 
In No. VII (B, vol. 76, p. 592) of these studies, dealing with the synthetic 
action of enzymes, evidence was adduced tending to prove that emulsin and 
maltase give rise respectively to maltose and “‘isomaltose.” In view of the 
results now brought forward, it is clear that the nature of the synthetic 
processes must be regarded as uncertain until definite proof is obtained that 
this or that enzyme is the one concerned in the formation of a particular 
biose. At present we see no reason, however, to doubt the validity of the 
arguments previously adduced, the results obtained on repeating the experi- 
ments having uniformly served to confirm the early observations. 
But in extending the inquiry painful experience has convinced us that it 
* ‘Chem. Soc. Trans.,’ 1907, vol. 91, p. 670. 
