no 



THE PROTEINS OF THE WHEAT KERNEL. 



appearance unlike the heat coagulum formed by most other proteins. Pro- 

 teins of similar behavior to gliadin are found in the seeds of other cereals, 

 such as rye, barley, maize, oats, and sorghum. That found in rye is prob- 

 ably identical with the gliadin of wheat, for a rigid comparison has not yet 

 revealed any difference. Both have the same ultimate composition, the 

 same solubility, the same physical properties, and yield the same amount of 

 ammonia and glutaminic acid on hydrolysis. The identity of the two, how- 

 ever, is not certain, and with our present knowledge can not be established. 

 The proteins of the other cereals above mentioned are distinctly different, 

 though similar, proteins. 



Proteins characterized by such ready solubility in strong alcoholic solu- 

 tions as are those found in these cereals have not been obtained from the 

 seeds of any other plants. 



The ultimate composition of gliadin has been fixed within narrow limits 

 by the accordant analyses of several investigators as follows : 



Gliadin yields on hydrolysis a larger amount of ammonia, glutaminic acid, 

 and proline than any other protein yet examined, no glycocoll or lysine, and 

 a relatively small amount of histidine and arginine, as the following analysis 

 shows : 



Products of hydrolysis of gliadin. 



P.ct. 



Glycocoll 0.00 



Alanine 2.00 



Amino-valerianic acid 0.21 



Leucine 5.61 



Proline 7.06 



Phenylalanine 2.35 



Aspartic acid 0.58 



Glutaminic acid 37-33 



Serine o. 13 



P.ct. 



Tyrosine 1 . 20 



Cystine 0.45 



Lysine 0.00 



Histidine 0.61 



Arginine 3. 16 



Ammonia 5.11 



Tryptophane present 



Total 65.81 



Although gliadin gives a strong Molisch reaction, which is commonly con- 

 sidered to indicate the presence of a carbohydrate group, it gives no furfurol 

 when distilled with hydrochloric acid, as does ovalbumin, which has been 



