1905. | Studies on Enzyme ‘Action. 595 
points of view is that the enzyme acts throughout by “ protecting” one or the 
other position, according as it belongs either to the e@- or to the A-class of 
hydrolysts, thereby practically preventing. condensation from taking place in 
more than one direction ; in other words, assuming that it be the function of 
the enzyme to bring water into the circuit of change at the precise spot where 
it is required to effect the hydrolysis of a biose, it might serve, when acting 
on the products of hydrolysis, to maintain water in such a position as to 
hinder the condensation from occurring in the direction which would involve 
the reversal of the operation of hydrolysis; condensation would then be 
confined to the alternative position and would give rise to the biose which is 
the correlative of that hydrolysed by the enzyme. 
There can be no doubt that the enzyme has a specific influence in 
promoting the formation of the biose which it cannot hydrolyse, as no action 
takes place in its absence or when the solution is heated sufficiently to 
destroy it. To understand the character of this influence, it should be 
remembered that «- and $8-methylglucoside have both been shown to be 
capable of entering into close association with maltase and with emulsin ; 
presumably, therefore, the two forms of glucose present in solution both 
combine with the enzyme. Inasmuch as the enzymes are capable of acting 
as hydrolytic agents, they must, like acids, be capable also of acting as 
dehydrating agents. Probably the two forms of glucose give rise to different 
results, because, while hydrolytic action prevails in the one system, in the 
other the dehydrating effect is alone exercised, the association of the 
a-enzyme with a-glucose being of such a nature that water is continually 
present and can be made use of at the centre where the condensation should 
take place, the dehydrating effect being therefore almost entirely in abeyance ; 
whilst in the enzyme-8-glucose system the configuration of the enzyme 
relatively to the @-glucose is such as to render hydrolysis impossible and 
consequently the dehydrating effect prevails. In both cases opportunity 
conditions action: the different actions are begotten of different opportunities. 
It is noteworthy that, under natural conditions, apparently only one 
product is formed, there being no evidence, for example, that isomaltose is 
ever present in the plant. If further investigation should render this 
conclusion absolute, it will follow that the control exercised under natural 
conditions is not merely that which the separated enzyme exercises. But 
attention must not be confined to the enzyme, as the argument used above 
tends to show that, even under the influence of maltase, maltose alone might 
be produced, if the conditions prevailing in the plant be such as to give rise 
only to a-glucose, provided. that the maltose were immediately withdrawn 
from the sphere of action, for example, by diffusion and fixation as starch; 
VOL. LXXVI.—B. 28 
