160 CHEMISTRY OF THE PROTEIDS CHAP. 



Glucose pentacetate C 1G H 22 O n - C 6 H 7 6 (C 2 H 3 0) 5 . 



Acetyl glucosamin C 8 H 15 6 N = C r H 12 5 N(COCH 3 ). 



Diacetyl glucosamin C 10 H 17 7 N = C 6 H 11 5 N(COCH 3 ) 2 . 



Pentacetyl glucosamin C 16 H 23 W N - C 6 H 8 5 N(COCH 3 ) 5 . 



If further glucosamin is injected into the circulatory system, it is 

 eliminated for the greater part, according to Fabian, 1 while proteids 

 containing glucosamin are completely oxidised. Ellinger and Gentzen 2 

 have shown analogously that tryptophane is completely oxidised when 

 administered subcutaneously, while it is excreted for the most part if 

 it is first converted into indol by the bacteria of the alimentary canal. 

 Glucosamin and indol, judging by these experiments, are therefore, 

 not normal products of animal metabolism, and just as indol is linked 

 up as indol-amino-propionic acid, so must glycosamin also be linked up 

 normally with some other radical (Cohnheim). 



In addition to glucosamin substances have repeatedly been dis- 

 covered which do not reduce, but which give the reaction of Molisch 

 (p. 8) and other reactions. For this reason the substances in 

 question are probably polysaccharids, which must be converted, in 

 the first instance, into monosaccharids before they can act as reduc- 

 ing bodies. Such a body has been found by Lobisch in the mucoid 

 of tendon, and by Hammarsten in helicoproteid ; the latter called 

 it sinistrin because of its Isevo-rotation. By treatment with pepsin, 

 succeeded by treatment with barium hydrate, Frankel obtained 

 ' albamin,' which he considers to be a nitrogen -containing biose. 

 After very prolonged peptic digestion Langstein 3 isolated from egg- 

 albumin a body, the analysis of which points to its being a dihexosamin. 

 This body gives rise to a reducing carbohydrate on being boiled for a 

 short time with hydrochloric acid. Here must also be mentioned the 

 so-called 'animal gum,' which Landwehr prepared by acting with 

 alkalies on mucin, and which Fohn, 4 Muller, and Weydemann also 

 prepared, according to Landwehr's directions, by boiling mucin in a 

 Papin's pot with 10 per cent potassium hydrate, or by digestion with 

 pepsin and trypsin. Animal gum is a light powder, soluble in water 

 and in 70 per cent alcohol. It is precipitated by phosphotungstic acid 

 and lead acetate and ammonia, and seems, according to Muller, to be 

 the lime salt of an organic acid. It is not attacked by diastase, but 

 by very short boiling is converted into glucosamin, yielding from 



1 R. Fabian, Zeitschr. f. physiol Chem., 27. 167 (1899). 



2 A. Ellinger and M. Gentzen, ffofmeister's Beitrage, 4. 171 (1903). 



3 L. Langstein, Hofmeisters Beitrage, 2. 229 (1902). 



4 O. Folin, Zeitschr. f. physiol. Chem. 23. 347 (1897). 



