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ENZYMES. 41
Other cleavage processes are certain so-called fermentation processes,
which are connected with the presence of living organisms, fungi and
bacteria of various kinds. Among these we include chiefly the alcoholic
fermentation and butyric acid fermentation of carbohydrates. Accord-
ing to the view based upon Pasteur’s investigations it has been gen-
erally considered that these processes are phases of the life of these
organisms and the name organized ferments or ferments have been given
to such organisms, especially to the ordinary yeast fungus.
A ferment, according to this view, is a living organism. By the name
enzyme, as introduced by Kuhne, we mean a product of the chemical
processes in the cells, which is active without the life of the cell and which
can be separated from the cell. The decomposition of invert sugar into
carbon dioxide and alcohol in fermentation is considered as a fermentative
process closely connected with the life of the yeast fungus. The inver-
sion of cane-sugar previous to fermentation is on the contrary, an enzymotic
process which is brought about by a body or mixture of bodies which
are formed in the fungus and which can be removed from the fungus
and are still active after the death of the fungus. Consequently fer-
ments and enzymes are capable of manifesting a different behavior toward
certain chemical reagents. Thus there exist a number of substances,
among which we may mention arsenious acid, phenol, toluene, salicylic
acid, boracic acid, sodium fluoride, chloroform, ether, and protoplasmic
poisons, which in certain concentration kill ferments, or at least retard
their action, but which do not noticeably impair the action of the enzymes.
The above view as to the difference between ferments and enzymes
has lately been essentially shaken by the researches of E. Buchner :
and his pupils. He has been able to obtain from beer-yeast, by grind-
ing and strong pressure, a cell-fluid rich in protein, and which when intro-
duced into a solution of a fermentable sugar caused a violent fermenta-
tion. The objections raised from several sides that the fluid expressed
still contained dissolved living cell substance has been so successfully
answered by Buchner and his collaborators that there is at present
no question that alcoholic fermentation is caused by a special enzyme or
mixture of enzymes called zymase, which is formed in the yeast-cell.
As from the yeast-cells so also from ether lower organisms, indeed
l
E. Buchner, Ber. d. deutsch. chem. Gesellsch., 30 and 31; E. Buchner and Rapp,
ibid., 31, 32, 34; H. Buchner, Stizungsber. d. Gesellsch. f. Morphol. u. Physiol, in
Munehen, 13 (1897), part 1, which also contains the discussion on this topic. See also
E. and H. Buchner and M. Hahn, Die Zymasegarung, Munehen (1903); Stavenhagen,
Ber. d. deutsch. chem. Gesellsch., 30; Albert and Buchner, ibid., 33; Buchner. ibid.
33; Albert, ibid., 33; Albert, Buchner, and Rapp, ibid., 35; in regard to the opposed
views see Macfadyen, Morris, and Rowland, ibid., 33; Wroblewski, Centralbl. f. Physiol.,
13, and Journ. f. prakt. Chem. (N. F.), 64.
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