84 THE PROTEIN SUBSTANCES. 



by HARRIES and LANGHELD l and the action of chlorine by HABERMANN and 

 EHRENFELD and PANZER. 2 



Nitric acid gives various yellow products, which turn reddish-brown in 

 alkaline solution. Of these we must especially mention the so-called xantho- 

 protein, besides nitrated proteoses and peptones. The xanthoprotein does not 

 yield any tyrosine on acid hydrolysis and it does not give the Millon or the lead- 

 blackening reactions. Among the cleavage products v. FURTH 2 has obtained a 

 melanoidin substance, xanthomelanoidin. 



On the nitration of the protamines (see below) KOSSEL 4 and co-workers have 

 obtained nitroprotamines which give nitroarginine on hydrolysis which shows that 

 the nitro groups have entered the guanidine groups of the arginine. 



By the dry distillation of proteins we obtain a large number of decomposition 

 products having a disagreeable burned odor, and a porous glistening mass of carbon 

 containing nitrogen is left as a residue. The products of distillation are partly 

 an alkaline liquid which contains ammonium carbonate and acetate, ammonium 

 sulphide, ammonium cyanide, an inflammable oil, and other bodies, and a brown 

 oil which contains hydrocarbons, nitrogenized bases belonging to the aniline and 

 pyridine series, and a number of unknown substances. 



The occurrence of protein substances which contain a carbohydrate 

 group has been known for a long time. The nature of this carbohydrate, 

 which can be split off by acid and which may amount to as much as 35 

 per cent, has been explained chiefly by the investigations of FRIEDRICH 

 MuLLER 5 and his students. They have shown that it is always an 

 amino-sugar, and generally glucosamine and perhaps galactosamine 

 as Jan exception. That so-called true proteins also yield a carbohydrate 

 on hydrolytic cleavage was first shown by PAVY, using ovalbumin. The 

 continued investigations of FR. MULLER, and others have demonstrated 

 that in these cases the carbohydrate is also glucosamine. A carbohy- 

 drate complex, although sometimes only to a very slight amount, has 

 been detected in other proteins, ovoglobulin, serglobulin, seralbumin, 

 peaglobulin, albumin of the graminese, yolk-proteid, and fibrin. In 

 other proteins, on the contrary, such, as edestin (of the hemp-seed) and 

 casein, myosin, pure fibrinogen, and ovovitellin, carbohydrates have 

 been sought for with negative results. All proteins hence do not contain 

 a carbohydrate group, and future investigators must therefore decide 

 whether the carbohydrate groups belong positively to the protein com- 



1 Blumenthal and Neuberg, Deutsch. med. Wochenschr., 1901; Orgler, Hofmeister's 

 Beitrage, 1; Harries and Langheld, Zeitschr. f. physiol. Chem., 51. 



2 Habermann and Ehrenfeld, Zeitschr. f. physiol. Chem., 32; Panzer, ibid., 33 

 and 34. 



3 See Maly's Jahresber, 30, p. 24. 



4 Kossel and Kennaway, Zeitschr. f. physiol. Chem., 72, with E. Wechsler, ibid., 

 78 and with F. Weiss, ibid., 78. 



6 In regard to the literature on this subject see the work of Fr. Miiller, Zeitschr. 

 f. Biologic, 42, and Langstein, Ergebnisse der Physiologie, Jahrg. I, Abt. 1, 63, Zeitschr. 

 f. physiol. Chem., 41, and Hofmeister's Beitrage, 6. See also Abderhalden, Bergell, 

 and Dorpinghaus, Zeitschr. f. physiol. Chem., 41. 



