156 CHEMISTRY OF THE PROTEIDS CHA;. 



transformation. E. Fischer 1 believes the oxy-amino- acids to be 

 especially concerned in this conversion into carbohydrates. How 

 important in this connection di-amino-propionic acid is has been 

 pointed out on p. 164. 



During the transformation of amino-acids into dextrose, the elimina- 

 tion of the amino-group is of course essential, and it is very interesting 

 to observe, firstly, how the grouping of atoms, as met with in the 

 a-amino-acids, is readily attacked by bacteria (see p. 100) and by the 

 oxidising forces within the animal body 2 (see also p. 106); and 

 secondly, how the nitrogen and the carbon of the albumin pursue 

 different paths in metabolism. 3 These observations are of the greatesl 

 biological interest, but as yet they throw but little light on tb' 

 chemistry of proteids. 



In the following pages only such praeformed carbohydrate-grouf 

 will be discussed as may be obtained, analogously to tyrosin o? 

 arginin, by dissociating albumins without allowing any disintegratior 

 or secondary processes to come into play. 



The first well-defined carbohydrate -compound isolated from ar 

 animal tissue was glucosamin, which Ledderhose 4 prepared bj 

 boiling the shells of lobster's claws in concentrated hydrochlori< 

 acid. Winterstein then obtained a similar body from fungus 

 cellulose. 5 



An identical carbohydrate group exists, without doubt, also in th< 

 mucins and mucoids, as the investigations of Landwehr, 6 Zanetti, 

 Hammarsten 8 and his pupils, 9 Morner, 10 Lobisch, 11 and Friedricl 



1 E. Fischer and A. Skita, Zeitschr. f. physiol. Chem. 35. 221 (1902) ; E. Fische 

 and H. Leuchs, Benefit d. deutsch. chem. Ges. 36. I. 24 (1903). 



2 H. Weiske and B. Schulze, Zeitschr. f. Biol. 20. 277 (1884) ; N. Zuntz (an< 

 Bahlmann), Arch. f. (Anat. u.} Physiol. 1882, p. 424. 



3 J. Frentzel (and N. Zuntz), ibid. 1899, p. 383 ; 0. Frank and F. v. Gebhard 

 Zeitschr. f. Biolog. 43. 117 (1902) ; 0. Frank and R. Trommsdorf, ibid. 43. 25i 

 (1902). 



4 Ledderhose, Ber. d. deutsch. chem. Ges. 9. 1200 (1878) ; Zeitschr. f. physiol 

 Chem. 2. 213 (1878-79), and 4. 139 (1880). See also Tiemann, Ber. d. deutsch. chew 

 Ges. 17. 241 and 19. 49. 



5 E. Winterstein, Zeitschr. f. physiol. Chem. 19. 521 (1894). 



6 H. A. Landwehr, ibid. 5. 371 (1881), 6. 74 (1881), 8. 114 (1883). 



7 C. U. Zanetti, Ann. di Chim. e Fermac. 12. (1897) ; in Maly's Jahresber. / 

 Tierchemie, 27. 31 (1897). 



8 0. Hammarsten, Zeitschr. f. physiol. Chem. 6. 194 (1882), 12. 163 (1887) 

 Pfluger's Arch.f. d. ges. Physiol. 36. 373 (1885) ; Zeitschr. f. physiol. Chem. 15. 20 

 (1891). 



9 E. A. Jernstrom, abstracted from the Swedish original by Hammarsten, Maly' 

 Jahresber. f. Tierchemie, 1O. 34 (1880). 



10 C. T. Morner, Zeitschr. f. physiol. Chem. 18. 61, 213, 233 (1893). 



11 W. F. Lobisch, ibid. 10. 40 (1885). 



