accelerates the decomposition of the same material, there may be cited the
demonstrated synthesis of isomaltose from glucose by maltase; the
production of ethyl butyrate from alcohol and butyric acid; and the
synthetic production of artificial fats, by the aid of the pancreatic
lipase; and the apparent synthesis of a protein from the same amino-acids
which may be obtained from it by hydrolysis under the influence of the same
protease, but under different environmental conditions.

ACTIVATORS AND INHIBITORS

The activity of enzymes is strongly influenced by the presence in the
solution of other bodies, usually, although not always, electrolytes. This
is probably due, in most cases at least, to the action of the electrolyte
upon the colloidal condition of the enzyme. All enzymes do not respond
alike to the action of the same electrolyte, however. The activity of
certain enzymes is enormously increased by the presence of a small amount
of acid; while the action of another may be absolutely inhibited by the
same acid in the same concentration. Thus, the activity of the amylase
found in the endosperm of many seeds is instantly stopped by adding to the
solution enough sulfuric acid to make it two-hundredth normal in strength;
while the same concentration of acid actually accelerates the activity of
some of the proteases.

Formaldehyde, hydrocyanic acid, and soluble fluorides usually inhibit both
the activity of a cell and of the enzymes which it contains; while other
antiseptics, such as toluene, xylene, etc., prevent the growth of the cell,
or organism, without interfering with the activity of the enzymes which may
be present. By the use of this latter type of antiseptics, it is possible
to distinguish between chemical changes which are involved in the actual
development of a cell and those which can be brought about in other media
by means of the enzymes which are contained in the cell.

Any substance which increases the catalytic activity of an enzyme is known
as an "accelerator," or "activator"; while one which prevents this activity
is called an "inhibitor," or "paralyzer."

A type of accelerating influence quite different from that of electrolytes
is found in the effect of certain amino-acids upon enzyme action. The
influence of small amounts of asparagine in enormously increasing the
hydrolytic effect of amylase is an example. There is no known explanation
for this type of activation of t