82 



THE PROTEINS OF THE WHEAT KERNEL. 



ences in the amount of histidiue found in them to be within the limits of 

 accuracy of these determinations. 



Kossel & Kutscher also found 3.05 per cent of arginine in the fraction 

 which they called gluten-fibrin, 2.75 per cent in their gliadin, and 3.13 per 

 cent in their mucedin. In determining the amount of protein hydrolyzed 

 they calculated the weight from the nitrogen in solution. If, as seems 

 probable, only one alcohol-soluble protein exists in this seed, namely, 

 gliadin, with 17.5 per cent of nitrogen, and that the nitrogen of their solu- 

 tions belonged to this protein, the proportion of arginine found by them 

 would be, respectively, 3.13, 2.79, and 3.25 percent, with which 3.16 per 

 cent agrees very closely. The results of this hydrolysis are given in table 17. 



Table 17. Gliadin. 



P.ct. 



Glycocoll 0.00 



Alanine 2.00 



Amino-valerianic acid 0.21 



Leucine 5.61 



a-proline 7.06 



Phenylalanine 2.35 



Aspartic acid 0.58 



Glutaminic acid 37-33 



Serine o. 13 



Tyrosine 1.20 



P.ct. 



Cystine 0.45 



Oxy-proline 



Lysine 0.00 



1 1 istidine 0.58 



Arginine 3. 16 



Ammonia 5. 11 



Tryptophane present 



65.78 



PROTEIN INSOLUBLE IN WATER, SALINE SOLUTIONS, AND ALCOHOL 



GLUTENIN. 



As already stated, extraction with the above-named solvents, applied suc- 

 cessively, removed but a part of the total protein contained in the wheat 

 kernel, that remaining being soluble only in dilute acids and alkalis. The 

 following extractions were next made to determine the nature of this body. 



Protein Extracted by Dilute Alkaline Solutions after Extracting the 

 Flour with 10 per cent Sodium-Chloride Brine and then with Dilute 

 Alcohol. 



After completely extracting from 4000 grams "straight flour" all the 

 protein soluble in 10 per cent sodium chloride solution, the residue was 

 freed wholly from protein soluble in cold alcohol of 0.90 sp. gr. The re- 

 sulting residue was then extracted twice with a large quantity of o. 1 per 

 cent potassium hydroxide solution. After standing 3 days at a tempera- 

 ture of 5 with frequent stirring, this extract was filtered off and allowed 

 to stand in a cold room until the greater part of the fine starch and other 

 impurities which had escaped filtration had settled. The solution, which 

 was still turbid, was decanted from the sediment and neutralized as exactly 

 as possible with 0.2 per cent hydrochloric acid, thereby producing a precipi- 



