UNIVERSITY 



OF ,. K y 

 ii SECONDARY DISSOCIATION-PRODUCTS ';. 91 



dealing with oxyprot-sulphonic and peroxyprot-sulphonic acids, two 

 oxidation-products of albumin. E. Fischer l and Steudel 2 have decom- 

 posed casein under ordinary pressure by boiling with caustic soda or 

 barium hydrate. In doing so, albumins pass through the stage of 

 alkali -albuminates and subsequently form albumoses and peptones, 

 therefore at first the same substances are obtained as after treating 

 albumins with acids. Schiitzenberger found leucin, amino-valerianic 

 acid, amino- butyric acid, alanin, tyrosin, phenylalanin, aspartic and 

 glutaminic acids, besides other amino-acids which were not isolated ; 

 Schulze and Bosshard found leucin, tyrosin, phenylalanin, aspartic 

 and glutaminic acids ; Bernert : lysin and histidin ; Steudel : lysin 

 and tyrosin ; E. Fischer : pyrrolidin-carboxylic acid. 



As has already been mentioned, treatment with fixed alkalies 

 renders all amino-acids optically inactive, but, in addition, it splits 

 off ammonia, so that instead of and along with the amino-acids we 

 obtain the corresponding simple acids, namely acetic, propionic, butyric, 

 and valerianic acids, and of course large amounts of ammonia; Haber- 

 inann and Ehrenfeld 3 found 3 -5 8 per cent in casein. 



Accompanying the above changes are still other processes which 

 lead to the formation of formic and carbonic acids. Schiitzenberger 

 stated oxalic acid to be also formed, but Habermann and Ehrenfeld 

 were unable to confirm this observation. Because of all these secondary 

 changes, the usual dissociation-products can no longer be found ; thus 

 Steudel failed to obtain arginin and histidin. 



By fusing albumins directly with solid potash the disintegration 

 becomes even more marked, as has been shown by Bopp 4 and Hinter- 

 berger, 5 and later by Kiihne, 6 Nencki, 7 Sieber and Schoubenko, 8 and 

 Rubner. 9 At first, again, amino-acids, leucin, and tyrosin 10 are formed, 

 but then the amino-acids give rise to the corresponding fatty acids ; 

 thus indol-amino-propionic acid is changed into skatol and indol, sub- 

 stances first observed by Kiihne and Nencki, while cystin yields 

 sulphuretted hydrogen n and mercaptane. 12 



1 E. Fischer, Zeitschr. f. physiol. Chem. 35. 227 (1902). 



2 H. Steudel, ibid. 35. 540 (1902).: 



3 J. Habermann and R. Ehrenfeld, ibid. 30. 453 (1900). 



4 N. Bopp, Liebig's Ann. 69. 29 (1847). 5 F. Hinterberger, ibid. 71. 70 (1849). 



6 W. Kiihne, Ber. d. deutsch. chem. Ges. 8. I. 206 (1875). 



7 M. Nencki, ibid. 8. I. 336 (1875) ; Journ. f. prakt. Chem. (2), 17- 97 (1878). 



8 N. Sieber and G. Schoubenko, Arch. d. Sciences biol. de St. Pttersbourg, 1. 314 

 (1892). 9 M. Rubner, Arch. f. Hygiene, 19. 136 (1893). 



10 N. Bopp, Liebig's Ann. 69. 29 (1847) ; F. Hinterberger, ibid. 71. 70 (1849). 



11 N. Sieber and G. Schoubenko, Arch. d. Sciences biol. de St. Petersburg, 1. 314 

 (1892). 



12 N. Sieber and G. Schoubenko, ibid. ; M. Rubner, Arch.f. Hygiene, 19. 136 (1893). 



