424 CHEMISTRY OF THE LEUCOMAINS. 



shown to exist preformed in germinating plants : Leucin, tyrosin, 

 phenyl alanin, amido valerianic acid, asparagin, glutamin, arginin, 

 histidin and lysin. 



The three last mentioned substances, the hexon bases, have been 

 only recently shown to be products of tryptic digestion. Indeed, 

 the studies of Kutscher ^ have shown that the so-called antipepton is 

 not a chemical substance possessing a definite formula, Cj^Hj^NjOj, 

 as Siegfried believes, but is rather a heterogeneous mixture from 

 which he was able to isolate leucin, tyrosin, aspartic and glutamic 

 acids, arginin, histidin and lysin. In other words trypsin, like sul- 

 phuric acid, if given sufficient time will completely split up the pro- 

 teid molecule and will not stop short, as has been heretofore held 

 with a resistant antipepton. An exactly similar condition is met 

 with in the auto-digestion of yeast where not only xanthin bases and 

 amido acids, but also hexon bases form (Kutscher^). It is of interest 

 to note that according to Levene ' arginin, histidin and uracil, and 

 possibly thymin, are formed during the auto-digestion of the pancreas. 

 From the liver of a case of acute yellow atrophy Taylor obtained 

 leucin and asparaginic acid but no hexon or purin bases. Hedin * 

 was the first to point out the presence of lysin in tryptic digestion of 

 fibrin and Kossel and Mathews found the three hexon bases in the 

 similar digestion of sturin. 



The investigations of Lawrow ° show that the proteid molecule is 

 also destroyed in peptic digestion. Thus in the sterile auto-digestion 

 of pigs' stomachs he obtained leucin, asparaginic and amido valerianic 

 acids but no tyrosin. Hexon bases were not present but instead 

 large amounts of cadaverin and putrescin. The latter two bases 

 undoubtedly resulting by the pepsin hydrolysis of the proteid. A 

 somewhat similar result was obtained by Kutscher * in the auto-diges- 

 tion of the thymus gland. Of still greater significance is the observa- 

 tion of Kutscher and Seemann' that in the small intestines albu- 

 moses and peptons are nearly absent and that leucin, tyrosin, lysin 

 and arginin are present as a result of energetic tryptic action. 



Haslam * has shown that the three bases exist in different amounts 

 in deutero- and hetero-albumose. Hart' found that the yield of 

 hexon bases was about the same in syntonin and protalbumose whereas 

 in heteroalbumose the relative amounts were different and to a cer- 

 tain extent depended upon the quantity of salt present. 



According to Emmerling *" the enzyme papayotin acting on blood 



^ZeUt. phyml. Chem., 25, 195 ; 26, 110 ; 28, 88 (1899). 



^ ZeUs. physiol. Chem., 32, 59. 



'Zeits. physiol. Chen., 32, 540 (1901). 



*ZeUs. phymol. Chem., 21, 298. 



^ Zeits. physiol. Chem., 26, 512 ; 33, 312. 



^ Zeits. physiol. Chem., 34, U7. 



'' Zeiis. physiol. Chem., 34, 543. 



^ Zeits. physiol. Chem., 32, 54. 



^ Zeiis. physiol. Chem., 33, 347. 



^"Beriehte, 35, 695, 700 (1902). 



