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OVOVITELLIN. 629
that the lecithin is chemically ui.ited with the vitellin (Hoppe-Seyler l
).
According to Osborne and Campbell, the so-called ovovitellin is a mix-
ture of various vitellin-lecithin combinations, with 15 to 30 per cent of
lecithin. The protein substance freed from lecithin is the same in all
these compounds and has the following composition: C 51.24, H 7.16,
N 16.38, S 1.04, P 0.94, O 23.24 pur cent. These figures differ somewhat
from those obtained by Gross for vitellin prepared by another method
(precipitation with [NH4] 2S04), namely, C 48.01, H 6.35, N 14.91-16.97,
P 0.32-0.35, S 0.88, and the composition of ovovitellin is therefore not
positively known. Besides the vitellin Gross found a globulin coagulat-
ing at 76-77° C. in a solution containing salt, and Pllmmer 2
found a
protein which he calls livetin which only contained 0.1 per cent phos-
phorus and which gave more monamino acids but less amide and diamino
nitrogen than vitellin.
On the pepsin digestion of ovovitellin, Osborne and Campbell
obtained a pseudonuclein with varying amounts of phosphorus, 2.52-
4.19 per cent. Bunge 3
prepared a pseudonuclein by digesting the yolk
with gastric juice, and his pseudonuclein, . he claims, is of great impor-
tance in the formation of the blood, and on these grounds he called it
hcematogen. This hsematogen has the following composition: C 42.11,
H 6.08, N 14.73, S 0.55, P 5.19, Fe 0.29, and O 31.05 per cent. The
composition of this substance may vary considerably even on using the
same method of preparation.
Vitellin is similar to the globulins in that it is insoluble in water, but
on the contrary soluble in dilute neutral-salt solutions (although the solu-
tion is not quite transparent). It is also soluble in hydrochloric acid of
1 p. m. and in very dilute solutions of alkalies or alkali carbonates. It
is precipitated from its salt solution by diluting with water, and when
allowed to stand some time in contact with water the vitellin is gradually
changed, forming a substance more like the albuminates. The coagu-
lation temperature for the solution containing salt (NaCl) lies between
70 and 75° C, or, when heated very rapidly, at about 80° C. Vitellin
differs from the globulins in yielding pseudonuclein by peptic digestion.
It is not always completely precipitated by NaCl in substance. The
ovovitellin isolated by Gross gave Molisch’s reaction. Neuberg4
has also split off glucosamine from the yolk and has identified it as nori-
1
Med. ehem. Untersuch., 216.
2
Osborne and Campbell, Connecticut Agric. Exp. Station, 23d Ann. Report, New
Haven, 1900; Gross, Zur Kenntn. d. Ovovitellin, Inaug.-Diss. Strassburg, 1S99;
Plimmer, Journ. Chem. Soc, London, 93.
3
Zeitschr. f. physiol. Chem., 9, 49. See also Hugounenq and Morel, Compt. Rend.,
140 and 141.
* Ber. d. d. chem. Gesellsch., 34.
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