450 PROTEINS 



Tyrosine, according to Shibata,* occurs in considerable 

 quantity in rapidly growing shoots of Japanese bamboos, and 

 in small quantity in seedlings of Lupinus albns f and Vicia 

 sativa ; % it has also been described as occurring with aspara- 

 eine in the root-tubers of Dahlia variabilis. 



Tryptophane has been found in seedlings of Lupinus albns, 

 Vicia sativa, and in Pisum sativum.^ 



Proline is obtained by the hydrolysis of a number of proteins 

 of vegetable origin, notably the prolamins, but has not so far 

 been found to occur as such in any plants. 



SYNTHESIS OF AMINO ACIDS IN THE PLANT. 

 With regard to the synthesis of amino acids within the 

 plant, it is of interest to note that in the laboratory Erlenmeyer 

 and Kunlin !| have been able to synthesize the acetyl and 

 formyl derivatives respectively of alanine and glycine by the 

 action of ammonia on glyoxylic acid, both of which sub- 

 stances are known to occur in plants. The changes involved 

 may be represented by the following formulae : — 



CHO CHjNHCHO 



2 I + NH, = I + H,0 + CO, 



COOH COOH 



Glyoxylic acid Formylglycine 



CH2NHCHO CH^NH., 



I + H,0 -^ I + HCOOH 



COOH " COOH 



Glycine 



Furthermore, Fischer and Schlotterbeck ^ synthesized a di- 

 amino acid by the action of ammonia on sorbic acid, an un- 

 saturated acid occurring in the unripe berries of the mountain 

 ash ; also another unsaturated acid belonging to the same 

 series as sorbic acid, namely, ^-vinyl acrylic acid, has by the 

 action of ammonia been converted into diamino valeric acid,** 

 and further, aspartic acid ft has been obtained by the action of 

 ammonia on fumaric acid. 



* Shibata : " J. Coll. Sci. Tokyo," 1900, 13, 329. 



t Schulze and Castoro : " Zeit. physiol. Chem.," 1906, 48, 387, 396. 



X Gorup Besanez : " Ber. deut. chem. Gesells.," 1877, 10, 781. 



§ Schulze and Winterstein : " Zeit. physiol. Chem.," 1910, 65, 431. 



II Erlenmeyer and Kunlin : " Ber. deut. chem. Gesells.," 1902, 35, 2438. 



^ Fischer and Schlotterbeck : id., 1904, 37, 2357. 



** Fischer and Raske : id., 1905, 38, 3607. 



tf Engel : " Compt. rend.," 1887, 104, 1805, and 1885, 106, 1677. 



