98 THE SYNTHESIS OF PROTEINS 



again to amino acid. The amino acids then combine to form 

 polypeptides which in turn give rise to the proteins. 



With regard to other views concerning the synthesis of 

 proteins, Treub,* from his investigations on the distribution 

 of, the periodic variation in the amount of, and cognate ob- 

 servations on the cyanogenetic glucosides,f concluded that 

 hydrocyanic acid is the first recognizable product of nitrogen 

 assimilation, and possibly is the first organic nitrogen com- 

 pound formed. Whilst on purely chemical grounds it is not 

 impossible that acetone cyanhydrin, (CH 3 ) 2 : C(OH)CN, may 

 be a stage in protein syntheis, Treub's conclusions are not 

 convincing : free hydrocyanic acid has not been identified 

 in plants, and its compounds may equally well result from the 

 oxidation of amino acids : in other words, the known facts 

 regarding compounds of hydrocyanic acid in the plant neither 

 prove nor disprove Treub's hypothesis.^ 



* Treub : " Ann. Jard. Bot. Buitenzorg," 1895, 13, 1 ; 1904. >9> 

 86 ; 1907, 21, 107. 



f See Vol. I., p. 253. 



t Rosenthaler : " Schweiz. Apoth. Ztg.," 1920, 58, 137; 1921, 59* 

 10, 22 ; " Biochem. Zeit.," 1923, 134, 215, 321. 



