20 



THE PROTEINS OF THE WHEAT KERNEL. 



THE ALBUMIN OP WHEAT FLOUR LEUCOSIN. 



A quantity of wheat flour was extracted with 10 per cent sodium-chloride 

 solution, the extract saturated with ammonium sulphate, the precipitated 

 protein dissolved in sodium-chloride brine, and the clear solution dialyzed 

 until all the globulin had been precipitated. The filtered solution was then 

 heated to 6o in a water-bath kept between 6o and 65 . After an hour the 

 precipitate was filtered off, washed thoroughly with water, alcohol, absolute 

 alcohol and ether, and dried. Before drying, the coagulum was a white, 

 voluminous, semisolid mass, which, when completely dried over sulphuric 

 acid, became dense and horny. This preparation, 1, after drying at 110 , 

 was found to have the composition shown in the following table : 



Another lot of 10,000 grams of floui was extracted with 10 per cent 

 sodium chloride solution and treated in the same way as the extract last 

 described. The albumin obtained weighed 6.4 grams and had the composi- 

 tion given in the above table, preparation 2. 



The filtrate from preparation 2 was then heated to 75 and 0.65 gram 

 of coagulum obtained, which on analysis gave the results shown in the table 

 on page 21, preparation 3. 



Another preparation was made from the same flour by extracting 10,000 

 grams with 10 per cent sodium chloride solution, filtering the extract, and 

 dialyzing at once. In this case the precipitation of the proteins with ammo- 

 nium sulphate was omitted. After complete dialysis the solution was filtered 

 from the globulin which had separated, and the solution heated at once to 

 90 a temperature high enough to precipitate all of the albumin. 



Dried over sulphuric acid, this preparation, 4, which in all respects resem- 

 bled 1 and 2, weighed 16.5 grams and when analyzed gave the results shown 

 in the table at the top of page 21. 



