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PROTEOSES AND PEPTONES. 127
which stand in connection with their strongly marked acid nature. Dilute
solutions of alkalies act more energetically on proteida than do acids
of corresponding concentration. In the first case a part of the nitro-
gen and often also the sulphur, is split off, and from this property we may
obtain an alkali albuminate by the action of an alkali upon an acid albu-
minate; but we cannot obtain an acid albuminate by the reverse reac-
tion (K. Mokner l
). This does not exclude the possibility that, by
a more severe acid treatment, products can be obtained which perhaps
correspond to those products obtained by a more mild alkali treatment.
The preparation of the albuminates has been given above. The
corresponding albuminate obtained by the action cf alkalies or acids
upon a proteid solution may be precipitated by neutralizing with acid
or alkali. The washed precipitate is dissolved in water by the aid of a
little alkali or acid, and again precipitated by neutralizing the solvent.
If this precipitate, which has been washed in water, is treated with
alcohol and ether, the albuminate will be obtained in a pure form.
In the preparation of acid as well as of alkali albuminates, proteoses and the
closely related albuminates are formed. The " alkali albumose " obtained by
Maajb 2
belongs to this class. The lysalbinic acid and protalbinic acid obtained
by Paal ’ from ovalbumin are likewise alkali albuminates. These have been
can tally studied by Skraup and his co-workers. 4
Desaminocdbtiminic acid is an alkali albuminate which Schmiedeberg 5
obtained
by the action of such weak alkali that a part of the nitrogen was evolved but the
quantity of sulphur remained the same. The proteid combination obtained by
Blum’ by the action of formol on proteid and called by him protogen, has similarities
with the alkali albuminates in regard to solubilities and precipitation, but is not
identical therewith.
2. Proteoses and Peptones.
Peptones were formerly designated as the final products of the decom-
position of protein bodies by means of proteolytic enzymes in so far as
these final products are still true proteins, while the intermediate prod-
ucts produced in the peptonization of proteins, in so far as they are
not substances similar to albuminates, were designated as proteoses
(albumoses, or propeptones) . Proteoses and peptones may also be
produced by the hydrolytic decomposition of the proteins with acids
1
Pfluger’s Arch., 17.
2
Zeitschr. f. physiol. Chem., 30.
3
Ber. d. d. chem. Gesellsch., 35.
4
Hummelberger, Lampel and Woeber, Monatsh. f. Chem., 30.
6
Arch. f. exp. Path. u. Pharm., 39.
6
Blum, Zeitschr. f. physiol. Chem., 22. The older investigations of Loew may
be found iu Maly’s Jahresber., 18S8. On the action of formaldehyde see also Benedi-
centi, Arch. f. (Anat. u.) Physiol., 1897; S. Schwarz, Zeitschr, f. physiol. Chem., 30;
Bliss and Xovy, Journ. of Exper. Med., 4.
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