MATERIAL TRANSFORMATIONS IN THE PLANT l6l 



NH— CO NH— CO 



i i II 



CO C— NHv CH C— NHv 



I II >CH II 11 )>CH 



NH— C W N C W 



Xanthin Hypoxanthin 



N= C.NH2 NH— CO 



II II 



CH C— NHv NH2.C C— NHv 



II II >CH II II >CH 



N— C W N C N^ 



Adenin Goania 



Among these decompositioa products are also the xanthia derivatives, caSein 

 (1-3-7-triinethyl-xanthia) and theobromin (3-7-dimethyl-xanthin'). 



Recent accounts of the formation of polypeptids in plants are very inter- 

 esting.^ These are in part primary and in part secondary, the latter being 

 formed by secondary synthetic processes. Tryosin and leucin are among the 

 primary products and are formed by protein hydrolysis due to proteolytic en- 

 zymes. Asparagin, on the contrary, is a secondary product, arising through the 

 transformation of primary products. Tyrosin and leucin, for example, occur 

 only in the first stages of the development of seedlings of Lupinus luteus, 

 while asparagin practically replaces these substances in later stages. The 

 following analyses' of lupine seedlings fifteen and eighteen days old show the 

 increase in asparagin content as the seedlings become older. [The values are 

 percentages on the basis of the total dry weight of the seeds before 

 germination.] 



Seedlings Seedlings 



IS Days Old 18 Days Old 



Nitrogen of proteins i .49 i .51 



Nitrogen of asparagin 3.85 4.23 



Nitrogen of other compounds 1.27 0.77 



Both groups of seedlings are seen to contain similar quantities of proteins, 

 but the amount of asparagin in the older seedlings is greater than that in the 

 younger ones. The increase in asparagin content arises at the expense of the 

 lower decomposition products, the amount of which is seen to be correspondingly 

 decreased. 



The amino acids formed in the primary decomposition of proteins are further 

 transformed without oxidation, and the transformation products thus pro- 

 duced have been called aporrhegmas,* Furthermore, methylation and spUtting 



' Weevers, Th., Die physiologische Bedeutung des Kaffeins und des Theobromins. Ann. Jard. 

 Bot. Buitenzorg II, 6 : 1-78. 1907. 



' Schulze, E., Neue Beitr&ge zur Kenntnis der Zusammensetzung und des Stoflwechsels der Keim- 

 pflanzen. Zeitsch. physiol. Chem. 47: 507-S69. 1906. 



s Merlis, M., Ueber die Zusammensetzung der Samen und der etiolierten Keimpflanzen von Lupinus 

 angustifolius L. Landw. Versuchsst. 48: 4I9-4S4- 1897. 



< Ackermann, D., and Kutscher, Fr., Ueber die Aporrhegmen. Zeitsch. physiol. Chem. 69: 265-272. 

 1910. Ackermann, D., Ueber ein neues, auf bakteriellem Wege gewinnbares, Aporrbegma. Ibid. 69: 

 273-281. 1910. Engeland, R., and Kutscher, Fr., Ueber ein methyliertes Aporrhegma des TierkSrpen. 

 /6>(i. 69: 282-285. 1910. J 



