330 PROTEINS 



OCCURRENCE OF AMINO ACIDS IN PLANTS. 



Leucine occurs as such in the buds of the horse-chestnut * 

 and many other plants. Isoleucine has been discovered by 

 Felix Ehrlich f in the residual molasses obtained from sugar 

 refineries. 



Lysine and histidine have been isolated from sprouting 

 plants by Schulze.} 



Arginine has been observed in the cotyledons of lupin 

 seeds and in etiolated pumpkin seeds, and also in several 

 species of conifers. 



Phenyl alanine was discovered by Schulze and Barbieri || 

 in etiolated germinating lupin seeds. 



Tyrosine, according to Shibata,1T occurs in considerable 

 quantity in rapidly growing shoots of Japanese bamboos, and 

 in small quantity in seedlings of Lupinus albus** and Vicia. 

 sativa /ff it has also been described as occurring with aspara- 

 gine in the root-tubers of Dahlia variabilis. According to 

 BerteljtJ tyrosine is converted into homogentisic acid by an 

 oxidase (see p. 361) contained in the plant, which is a change 

 similar to the one produced in the human body in the condi- 

 tion known as alkaptonuria. Schulze and Castoro, II II how- 

 ever, deny the accuracy of these observations. 



Tryptophane has been found in seedlings of Lupinus albus, 

 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. 



* Schulze and Barbieri: "J. prakt. Chem.," 1882, 15, 145; Schulze and 

 Winterstein : "Z. physiol. Chem.," 1902, 35, 299. 



t Ehrlich : "Ber. deut. chem. Gesells.," 1904, 37, 1809. 



JSchulze : "Z. physiol. Chem.," 1899, 28, 465. 



Schulze and Steiger : "Z. physiol. Chem.," 1887, n, 43; "Ber. deut. 

 chem. Gesells.," 1886, 19, 1177. 



1 1 Schulze and Barbieri: "Ber. deut. chem. Gesells.," 1881, 14, 1785. 



ITShibata: "J. Coll. Sci. Tokyo," 1900, 13, 329. 



** Schulze and Castoro: "Z. physiol. Chem.," 1906, 48, 387, 396. 



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



j:Bertel: " Ber. deut. bot. Gesells.," 1902, 20, 454. 



Wolkow and Baumann: "Z. physiol. Chem.," 1891, 15, 266. 



|| || Schulze and Castoro : loc. cit. 



HIT Schulze and Winterstein : "Z. physiol. Chem.," 1910, 65, 431. 



