n8 



THE PROTEINS OF THE WHEAT KERNEL. 



assumed that these two proteins are present in equal quantities in wheat 

 flour, an assumption that in most cases is nearly correct, the relative propor- 

 tion of the amino-acids yielded by the proteins of wheat flour is closely 

 shown by the following figures, which are the mean of those found for 

 gliadin and glutenin. In comparison with these are given the figures, at 

 present available, for some of the other forms of food protein. Such a com- 

 parison is at present unsatisfactory, owing to the lack of data now available, 

 but it will serve a useful purpose in indicating the wide differences between 

 these food proteins, and will emphasize the importance of obtaining more 

 information in regard to this question. 



Products of hydrolysis of some food proteins. 



Glycocoll 



Alanine 



Amino-valerianic acid. 



Leucine 



Proline 



Phenylalanine 



Aspartic acid 



Glutaminic acid 



Serine 



Tyrosine 



Cystine 



Lysine 



Histidine 



Arginine 



Ammonia 



Tryptophane 



Owing to the lack of data, it is not yet possible to compare the relative 

 proportion of the amino-acids which the food proteins yield except in respect 

 to glutaminic acid, ammonia, arginine, histidine, and lysine. The amount 

 of glutaminic acid which the gluten proteins yield is far greater than that 

 yielded by any of the other food proteins, with the exception of gliadin from 

 rye and hordein from barley. The proteins of the legumes and nuts which 

 are used as food yield from 15 to 20 per cent of glutaminic acid, so that the 

 mean amount of this amino-acid from the wheat protein is nearly twice as 

 large. The same also is true of ammonia. 



The proportion of arginine from wheat gluten is relatively small compared 

 with that from most other seed proteins, many of which yield from 10 to 16 

 per cent of this base. 



