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U. SUZUKI 



parts of the plants would be evident. According to Emvierling 

 J amido-acids are formed in the leaves synthetically and are 

 transported to the growing seeds. In the growing seeds or 

 fruits themselves he found more amides (asparagine and gluta- 

 mine) than amido-acids as leucine. ^'^ I am, however, of opinion 

 that the amido-acids. in the leaves are not formed directly by 

 synthesis, as Eminerling ■axvA others suppose, but are the products 

 of decomposition of proteids, only the amides such as asparagine 

 and glutamine being the products of direct synthesis ; these are 

 formed from ammonium salts or nitrates in all those cases, in 

 which not all the conditions for the production of proteids are 

 fulfilled/"' Furthermore, the asparagine found in the growing 

 fruits may either be the product of direct synthesis or, as Loezu 

 has surmised, a product of oxidation of other amido-acids, for 

 which hypothesis I Viished to adduce facts. I therefore paid 

 attention to the following questions : 



1st. — Are proteids decomposed in the leaves, and do the amido- 

 products thus formed migrate into the other jaarts of the plants 



2nd. — Is gradual oxidation of these amido-acids to 

 asparagine observable ? 



3rd. — Are amido-compounds, as leucine and asparagine, 

 under certain conditions, a better source of nitrogen for protein 

 production in fruits and roots than nitrates 



I. We know that proteids are protected to a certain degree 

 by carbohydrates and that with the gradual disappearance of the 

 carbohydrate, the proteids are more and more attacked by 

 enzymes, as shown b}" E. Schulze who found that plants kept 

 for a number of daj^s in darkness, show an increase of asparagine 

 and a decrease of proteids.'*' 



(1) The writers 011 the subjects do not make sufficient distinction between the 

 amides and amido-acids. It has become, however, very clear that a different mode 

 of formation and different functions have to be ascribed to asparagine (and perhaps 

 also to glutamine) than those given to the amido-acids such as leucine and tyrosine. 

 The amount of leucine is generally very much smaller than that of asparagine ; 

 thus, for instance, E. Schulze obtained from 7 kilo of Vicia faha six weeks old, grown 

 in the field, only 0.5 gram leucine and neither tyrosine nor phenyl amido-propionic acid. 



(2) This Bull. II. No. 7. 



(3) On these last two points I will communicate a later scries of experiments. 



(4) Asparagine, however, must not Ix; considered as a direct product of protcid 

 decomposition, but according to Loetu's view, .as the final product of metalx)lisni, by 

 which the previously formed leucine, tyrosine, arginine, lysine etc. are gradually oxidized 

 whereby asparagine from the remaining fragments is formed. 



