828 THE ROLE OF NITROGEN, ETC., I., 



lecithins, result cholin and betain; and by the further decom- 

 position of these, trimethylamine. (4) The glucosides yield their 

 hydrocyanic acid, aldehydes, hexose and pentose sugars. 



(b) Anabolism. — The decomposition of the reserve proteins in 

 the seed is followed by the regeneration of protein from the cleav- 

 age-products, and in our experiments it would be almost impossible 

 to distinguish the katabolic from the anabolic compounds. But 

 since the formation of protein greatly decreases in absence of 

 light, we are thus enabled, by etiolation of the seedling, to obtain 

 an accumulation of the intermediate bodies, i.e., of the precursors 

 of the proteins. 



Now when the amino-acids are observed to decrease gradually 

 as stated above, there is a corresponding increase in the amount 

 of amides — asparagin, glutamin, and others. The following 

 example, also from Schulze's results, shows this increase. 



The nitrogen of asparagin in etiolated seedlings of Lupinus 

 angustifolius : — 



Resting seeds. 1-week seedling. 2-weeks' seedling. 3-weeks seedling. 

 Nil. 27% 54% 00% 



per cent, of the total nitrogen present. 



The amino-bodies are not always consumed at the same rate or 

 in the same proportion; some are used up almost immediately, 

 while others, such as arginin in Lupinus luteus, accumulate, the 

 formation of the latter in hydrolysis exceeding its consumption. 

 Then again, asparagin and glutamin often replace each other, as,, 

 for example, in Cucurbita seedlings some cultures contained 

 large amounts of glutamin and only a little asparagin, while 

 others contained only the latter, glutamin not being found. 



When seedlings are subjected to aseptic autodigestion, there 

 are formed, by zymolysis, mono- and di-amino-acids, and ammonia. 

 Castoro(92) in one experiment found the amount of ammonia- 

 present to be about 0'2 % of the dry weight. Many investigators 

 have believed that this ammonia is not the result of oxidation of 

 protein, but of the activity of special enzymes, which Shibata(93) 

 names amidases, acting on amides. On the other hand we have 





