Full resolution (JPEG) - On this page / på denna sida - II. The Protein Substances - II. Compound Proteins - A. Glycoproteins (glucoproteins) - 2. Chondroproteins
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AMYLOID. 173
per cent. The aorta amyloid of man and of the horse contained respect-
ively C 49.6 and 50.5; H 7.2; N 14.4 and 13.8; S 2.3 and 2.5 per cent.
As we cannot tell whether the amyloid analyzed was pure or not the
results are of questionable value.
According to older investigations amyloid splits, by the action of
alkali, into protein and chondroitin-sulphuric arid (see Chapter IX),
and according to Krawkow it is therefore a firm, perhaps ester-like
combination of this acid with protein. The protein, from the investiga-
tions of Neuberg, is of a basic nature and most comparable to the
histones. The investigations of Mayeda do not coincide with this view
as the amyloid protein obtained by him did not behave like a histone.
Its content of hexone bases was not greater than that of the proteins
of the normal organs and this amyloid protein did not yield any his-
tone-peptone. To all appearances, different investigators have worked
with different substances and it is possible that in the amyloid degenerated
organs partly chondroproteins and partly amyloid proteins may occur,
both of which give the color reactions.
Amyloid is an amorphous white substance, insoluble in water, alcohol,
ether, dilute hydrochloric and acetic acids. It is soluble in concen-
trated hydrochloric acid or caustic alkali with decomposition. On boil-
ing with dilute hydrochloric acid it yields sulphuric acid and a reducing
substance. It is not dissolved by gastric juice, according to Krawkow,
which agrees with most of the older reports. It is nevertheless changed
so that it is soluble in dilute ammonia, while the typical amyloid is
insoluble therein. Neuberg finds on the contrary that amyloid (from
liver) is digested by pepsin as well as by trypsin, although more slowly
than fibrin, and that it is also destroyed in autolysis, so that in life an
absorption is possible. The amyloid from the " sago " spleen studied
by Hanssen showed the same behavior with gastric juice as Krawkow
found, while trypsin, as well as autolysis for months, was without action.
Mayeda’s amyloid was gradually dissolved by gastric juice.
Amyloid gives the xanthoproteic reaction and the reactions of Mil-
lon and Adamkiewicz-Hopkins. Its most important property is its
behavior with certain coloring matters. It is colored reddish-brown
or a dingy violet by iodine; a violet or blue by iodine and sulphuric
acid; red by methylaniline iodide, especially on the addition of acetic
acid; and red also by aniline green. Of these color reactions those with
aniline dyes are the most important. The iodine reaction appears less
constant and is greatly dependent upon the physical condition of the
amyloid. The color reactions are due to the presence cf the chondroitin-
sulphuric acid component, but this stands in opposition to the behavior
of the intact amyloid obtained by Hanssen from the " sago " spleen
and the amyloprotein of Mayeda.
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