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134 THE PROTEIN SUBSTANCES.
The hetero- and protoproteoses *are not, according to our present
views, the only primary proteoses. In the proteose fraction obtained
on saturating with ammonium sulphate in neutral liquids, which should
contain secondary proteoses only, primary proteoses such as the gluco-
proteose (Pick), which contains a carbohydrate group and the so-called
synproteose (Hofmeister l
) occur. It is no longer sufficient to consider
an unequal ability to be salted out, as an essential difference between
the primary and secondary proteoses.
There is no doubt that there exists a large number of so-called pro-
teoses having various precipitation properties, and different other prop-
erties and new differences appear, while working with them according to
different methods. For example Rona and Michaelis 2
find that cer-
tain proteoses are precipitated by mastic emulsion while others are not.
Those that are precipitatable by mastic, can all be salted out, while all
those that can be salted out are not all precipitated by mastic. The
hetero- and protoproteoses act, according to Zunz 3
like strong protec-
tion colloids toward colloidal gold, which is not the case with the others,
and also, according to this worker, the so-called proteoses are more readily
precipitated by chondroitin-sulphuric acid and acetic acid than the so-
called secondary proteoses. According to Hunter 4
only the primary
proteoses are precipitated by protamines while the secondary are not.
It is also possible that numerous intermediary members exist between
those proteoses which stand close to the original protein and those that
are further removed. The difficulties in isolation and purification of
these different members are so very great that the proteoses thus far
isolated must not be considered as chemical individuals. Under these
circumstances the above-mentioned differentiation and classification
of the various proteoses is of little value and a more detailed discus-
sion of the properties of the various proteoses thus far isolated is with-
out interest.
It would be of great interest if certain differences in the chemical
structure of the different proteoses could be determined with certainty.
Such differences are claimed to have been found in certain cases. Thus
Hart has found that the heteroproteose (from muscle syntonin) was
considerably richer in arginine and poorer in histidine than the proto-
proteose, and Pick has also found marked differences between the hetero-
and protoproteose from fibrin. The hetero-proteose yields very little
1
Ueber Bau unci Gruppirung der Eiweisskorper, Ergebnisse der Physiol., Jahrg. I,
Abt. 1 , 783.
"-
Biochem. Zeitsohr., 3.
3
Arch, internat. d. Physiol., 1 and 5, and Bull. Soc. Scienc. med. et natur. Brux-
elles, (54.
Mourn, of Physiol., 37.
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