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PROTEINS OF THE LIVER. 383
(0.28-1.3 per cent) of this globulin as well as the insolubility of the pre-
cipitates produced by little acid, in an excess of acid, and in neutral salt-
seem to indicate that we here have a mixture which consists chiefly of
nucleoproteins and not of globulins. The almost complete digestibility
with pepsin-hydrochloric acid does not controvert this assumption,
because, as is known, nucleoproteins may on digestion yield no residue
(see Chapter II). Nor can we be positive concerning the nature of
the liver-globulin found by Dastre, 1
having a coagulation temperature
of 56° C. The proteins extractable from the liver without modification
must be thoroughly investigated.
Besides the above-mentioned proteins, which are very soluble, the
liver-cells contain large quantities of difficultly soluble protein bodies
(see Pl6sz). The liver also contains, as first shown by St. Zaleski
and later substantiated by several other investigators, ferruginous
proteins of different kinds.2
. The chief portion of the protein- substances
in the liver seems in fact to consist of ferruginous nucleoproteins. On
boiling the liver with water, such a nucleoprotein or perhaps several
are split, and a solution is obtained containing a nucleic-acid-rich nucleo-
protein or a mixture of these which are precipitable by acids. This
protein or protein mixture, which has been called ferratin by Schmiede-
berg,3
has been studied by Wohlgemuth.4
The quantity of phos-
phorus was 3.0fi per cent. As cleavage products on hydrolysis he found
/-xylose, or at least a pentose, the four nuclein bases, and also arginine,
lysine (and histidine?), tyrosine, leucine, glycocoll, alanine, a-proline,
glutamic acid, aspartic acid, phenylalanine, oxyaminosuberic acid, and
oxydiaminosebacic acid (see Chapter II). The /-xylose depends, no
doubt, at least in part, upon the guanvlic acid isolated from the liver,
by Levene and Mandel,5
and the finding of adenine among the cleavage
products also indicates the presence of a thymonucleic acid. There does
not seem to be any doubt that the ferratin, as above stated, is a mixture,
and the correctness of this assumption is shown by the recent investiga-
tions of Scaffidi and Salkowski.6
1
Pohl, Hofmeister’s Beitrage, 7; Dastre, Compt. rend. soe. biolog.. 58.
2
St. Zaleski, Zeitschr. f. physiol. Chem., 10, 486; Woltering, ibid., 21; Spitzer,
Pniiger’s Arch., 67.
’ Arch. f. exp. Path. u. Pharm., 33; see also Vay, Zeitschr. f. physiol. Chem.. 20.
Wohlgemuth, Zeitschr. f. physiol. Chem., 37, 42, and 44, and Ber. d. d. chem.
Gesellsch., 37. See on liver nucleoproteins also Salkowski, Berl. klin. Wochenschr.,
1895; Hammarsten, Zeitschr. f. physiol. Chem., 19; Blumenthal, Zeitschr. f. klin. Med.,
34.
5
Bioch. Zeitschr., 10.
•Scaffidi, Zeitschr. f. physiol. Chem., 58; Salkowski, ibi>1., 58.
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