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ENZYMES. 47
Ave must mention the two diamines, cadaverine or pentametbylenediamine,
C5H14X2, and putrescine or tetramethylenediamine, C4H12N2, which
have awakened speeial interest because they occur in the contents of the
intestine and in the urine in certain pathological conditions, especially
in cholera and cystinuria. 1
The putrefaction bases marcitine, CsHigNa,
putrine, C11H26X2O3, and riridinine, C8H12N2O3, isolated by AcKER-
mann, also belong to this group. Of special interest is the bacterial
poison isolated by Faust,2
called sepsine, C8H14N2O2, which is the sub-
stance producing the characteristic toxic action of putrefactive masses.
Sepsine was prepared by Faust as a crystalline sulphate which, on repeated
evaporation of its solution, was readily converted into cadaverine sulphate.
Of especially great interest are the toxines which are found in the
higher plants and animals, like the jequirity-bean and castor-seed, in
the poison of snakes and spiders, in blood-serum, etc., and particularly
those produced by pathogenic micro-organisms have an unmistakable
relation to the enzymes. A closer study of these various bodies, lysines,
agglutinines, toxines, etc., as well as of the antitoxines and the theory
of immunity, does not lie within the scope of this work, but on account
of the great importance of the subject it will be briefly discussed on
page 66.
Classification of the Enzymes. If we exclude those processes which
are the result of several enzymotic reactions (i.e. autolysis, putrefaction)
then the most important enzymotic processes studied so far are the fol-
lowing :
1. Hydrolytic cleavage processes.
2. Cleavages of another variety (fermentation).
3. Oxidations.
We have no general chemical reaction in the ordinary sense which
is common to all enzymes or ferments and each enzyme is characterized
by its action and by the conditions under which this action is developed.
As the action of an enzyme upon a substance, or related substances, or
groups is limited therefore these substances or groups are called the
substrate of the enzyme.
In regard to the terminology it must be remarked that an enzyme
is often named after the substrate (amylase, protease, lipase); in other
cases the kind of action determines the name (oxidase, reductase) and
finally one of the products produced by its action forms the basis for
the name (alcoholase).
^ee Brieger, Berlin, klin. Wochenschr., 1887; Baumann and Udransky, Zeitschr.
f. physiol. Chem., 13 and 15; Brieger and Stadthagen, Berlin, klin. Wochenschr.. 1889.
2
Faust, Arch. f. exp. Path. u. Pharm., 51; Ackermann, Zeitschr. f. phvsiol. Chem.,
54 and 57.
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