iv THE HEMI- AND ANTI-GROUPS 149 



Amongst the products of peptic digestion Neumeister distinguished 

 also the anti- and the hemi-albumoses. This question was then taken 

 up in Hofmeister's Laboratory by Pick, 1 who made out that of the 

 two primary albumoses, the protalbumose belongs to the hemi-group, 

 while the hetero-albumose belongs to the anti-group. He also 

 established other chemical differences ; the hemi-group contains the 

 tyrosin and tryptophane, while the anti-group includes the glycocoll 

 and phenylalanin. According to Pick's definition, casein seemed to 

 be pure hemi-proteid, while gelatine was pure anti-proteid. Sub- 

 sequently Kutscher 2 succeeded by very prolonged autodigestion of 

 the pancreas to reach a stage where the biuret-reaction either failed 

 altogether or was only very slightly marked, and the conclusion was 

 arrived at that Kiihne's classification was only a relative one. 

 Kiihne's view has, however, been confirmed quite recently by E. Fischer 

 and Abderhalden, 3 who found that one or several polypeptids remain 

 unacted upon by trypsin even after very prolonged digestion, but 

 that they can be converted into amino-acids by treatment with acids. 

 The substances in question do not, however, give the biuret-reaction, 

 which is not very material, as has already been explained. In 

 their composition they agree with anti - albumin, for they contain 

 glycocoll and phenylalanin, further a-pyrrolidin-carboxylic acid, while 

 tyrosin and tryptophane are completely split off'. Leucin, alanin, 

 aspartic and glutaminic acids are present both in the hemi- and in the 

 anti-groups. Cystin, serin, and the di- amino-acids have not been 

 especially investigated, but Kutscher's 4 previous work shows that they 

 are liberated, at least partly, by trypsin. Ammonia is also liberated by 

 tryptic digestion, according to Hirschler, 5 Stadelmann, 6 and Dzierzgowski 

 and Salaskin. 7 Fischer and Abderhalden have observed that tyrosin 

 is especially readily liberated, which was also noticed when Fischer 

 and Bergell 8 subjected fibroin to tryptic digestion. Leucin, alanin, 

 etc., are liberated later than is tyrosin. 



Siegfried 9 arrived at identical results : he found " that by the 



1 E. Pick, Zeitschr. f.physiol. Chem. 28. 219 (1899). 



2 F. Kutscher, ibid. 28. 88 (1899) ; Eadprodukte der Trypsinverdauung, Marburger 

 Habilitationsschrift, Strassburg, 1899. 



3 E. Fischer and E. Abderhalden, Zeitschr. f. physiol. Chem. 39. 81 (1903). 



4 F. Kutscher, Endprodukte der Trypsinverdauung, Marburg, 1899. 



5 A. Hirschler, Zeitschr. f. physiol. Chem. 10. 302 (1886). 



6 E. Stadelmann, Zeitschr. f. Biolog. 24. 261 (1888). 



7 S. Dzierzgowski and S. Salaskin, Zentralbl. f. PhysioL 15. 249 (1901). 



8 E.Fischer,C%emfer^wi0,1902,II.p.939. (Karlsbader Naturforscherversamraluug.) 



9 M. Siegfried, Zeitschr. f. physiol. Chem. 38. 259 (1903) ; F. Miiller, ibid. 38. 265 

 (1903) ; M. Siegfried, Ber. d. sachs. Oes. d. Wissensch. zu Leipzig, math.-phys. Kl.. 

 1903, p. 63. 



