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162 THE PROTEIN SUBSTANCES.
Arginine has been prepared synthetically from ornithine (a-5-diamino-
valeric acid) and cyanamide by Schulze and Winterstein. Recently
Sorensen and Hoyrup x
have prepared oM-arginine from ornithuric
acid. The a-monobenzoyl ornithine obtained by splitting ornithuric
N
acid with — barium hydrate yields a-benzoylamino-5-guanido-valeric
5
acid with cyanamide and this on boiling with hydrochloric acid gave
S-guanido-a-aminovaleric acid (eW-arginine)
.
Arginine crystallizes in rosette-like tufts, plates, or thin prisms, is readily
soluble in water with alkaline reaction and almost insoluble in alcohol.
With several acids and metallic salts it forms crystalline salts and double
salts respectively. Its acidified watery solution is precipitated by phos-
photungstic acid. The most important salts are the copper-nitrate
(C 6Hi4N402)2.Cu(N03)2+3H20 and the silver salts
C6Hi4N402.HN03+AgN03
(the more readily soluble) and CeHuN^.AgNOa+^O (the more
difficultly soluble), and its compound with picrolonic acid (Steudel 2
).
Arginine is dextrorotatory. For arginine-chloride in watery solu-
tion with excess of hydrochloric acid, Gulewitsch 3
found (a) D = +21.25°
at 20° C. The arginine obtained by Kutscher in the tryptic digestion
of fibrin was racemic arginine. As found by Kossel and Weiss (see
page 112) arginine or more properly the ornithine is very easily
racemerized within the protein molecule by the action of alkali. The
racemic arginine can, as Riesser 4
has shown, during cleavage by means
of arginase, yield Z-arginine, which is an asymmetric change. In^putre-
faction arginine yields ornithine, guanidine, putrescine and 5-amino-
valeric acid.
/NH2
Agmatine (guanidobutylamine), C6H14N4 = HN.C<;
\NH.CH2 (CH2 ) 2 .CH2NH2 ,
is a base obtained by Kossel in the hydrolysis of herring sperm, and later by
Kutscher and Engeland 5
from ergot. Kossel has also obtained it synthetically
from cyanamide and tetramethylendiamine, and in this manner proved its con-
stitution. It is produced from arginine by splitting off C02 and bears the! same
relation to arginine that putrescine does to ornithine and cadeverine does to
lysine (see below). Agmatine gives several crystalline salts as described by
Kossel. It is precipitated by phosphotungstic acid.
Schulze and Winterstein, Ber. d. d. chem. Gesellseh., 32 and Zeitschr. f. physiol-
Chem., 34; Sorensen and Hoyrup, Ber. d. d. chem. Gesellseh, 43 and Zeitschr. f. physiol-
Chem., 76.
2
Zeitschr. f. physiol. Chem., 37 and 44.
3
Ibid., 27.
4
Kutscher, Zeitschr. f. physiol. Chem., 28 and 32; Riesser, ibid., 49.
6
Kossel, ibid., 66 and 68; Engeland and Kutscher, Centralbl. f. Physiol., 24, 479.
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