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CEREBROSIDES. 609
Sphingomyelin, is a diaminomonophosphatide which Thudichum prepared
from the brain and is the chief phosphatide obtainable from the impure protagon
mixtures. Rosenheim and Tebb obtained it, as above mentioned, from the
protagon. It has been given the formula ( , J H l „ 1 Xd)
09+H20. As cleavage
products an alcohol, Bphingol, iieurin, cholin, according to ROSENHEIM and Tebb,
the base sphingosin (see cerebron) and sphingostearic acid have been obtained.
Sphingomyelin is soluble with difficulty in cold alcohol but readily soluble in hot
alcohol and crystallizes therefrom in needles. It is insoluble in ether. In regard
to the specific rotation see above in reference to protagon. Amidomyelin (Thud-
ichum) is another diaininomonophosphatide of an unknown constitution and of
an uncertain composition. Its existence is uncertain.
Sahidin was found by Fu.vxkel 1
in the brain, and is a triaminodiphosphatide,
whose cadmium compound has the formula CsoHic7X3P20i2.3CdCl2 . It is a crys-
talline powder which is insoluble in water, cold ethyl or methyl alcohol and in
ether. It is soluble with difficulty in warm alcohol but readily soluble in chloro-
form and hot benzene. It yields saturated and unsaturated fatty acids, choline
and glycerophosphoric acid.
Leucopoliin is an unsaturated phosphatide found b}r
Frankel and Elias 2
in
the brain and which is a decaminodiphosphatide or a pentaminomonophosphatide.
It crystallizes from boiling alcohol on cooling. It does not contain any methylated
base but does contain a carbohydrate group.
Sulphatide is the name given by Koch 3
to a sulphurized and phosphorized
product obtained from the human brain which separates from warm pyridine
on cooling as a crystalline, granular mass. It contains phosphatide, sulphuric
acid and cerebroside and is claimed to be phosphatidesulphuric acid cerebroside.
Cerebrosides.
On decomposing protagon (or the protagons), or the brain substance
by the gentle action of alkalies we obtain, as cleavage products, as above
stated, one or more bodies which Thudichum has embraced under the
name cerebrosides. The cerebrosides are nitrogenous substances free
from phosphorus, which yield galactose on boiling with dilute mineral
acids. With concentrated sulphuric acid they first give a yellow and
then a purple-red coloration. With sulphuric acid and cane-sugar
they give a purple coloration directly. The cerebrosides isolated from
the brain are cerebrin, homocerebrin, phrenosin, kerasin, encephalin,
and cerebron, but it must be remarked that there is no doubt that
sometimes the same body of varying purity has received different names.
According to Levene and Jacobs 4
it must be admitted that the cere-
brosides are mixtures of stereoisomeric substances.
Cerebrin. Under this name W. Muller 5
first described a nitrog-
enous substance, free from phosphorus, which he obtained by extracting,
with boiling alcohol, a brain-mass which had been previously boiled with
1
Bioch. Zeitschr. 24.
2
Frankel and Elias, Bioch. Zeitschr. 28.
3
Zeitschr. f. physiol. Chem. 70.
4
Journ. of biol. Chem. 12.
B
Annal. d. Chem. u. Pharm., 105.
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