THE: PROTEINS OF THE WHEAT KERNEL. 

 4. Composition of albumin prepared from various cereals. 



In an earlier paper on the ' ' Chemical Nature of Diastase ' ' * I pointed out 

 that diastatic action appeared to be always associated with leucosin. Since 

 extracts of wheat embryo were so rich in leucosin, the diastatic power of the 

 germ meal was determined by extracting with four times its weight of water, 

 and, under the conditions of Litner's test, o. 10 cc. of the extract so made, 

 when added to 10 cc. of a 2 per cent solution of soluble starch, formed within 

 i hour, at 20, enough sugar to reduce 5 cc. of Fehling's solution. The 

 o.io cc. of extract corresponds to 25 mg. of the germs, from which it is seen 

 that this meal possesses high diastatic power, though it is inferior in this 

 respect to active malt. 



HYDROLYSIS OF LEUCOSIN. 



In order to determine the proportion of the different products which are 

 formed by boiling proteins with strong acids, it is necessary to use relatively 

 large amounts of the protein. Commercial wheat-germ meal was therefore 

 used in order to obtain a sufficient quantity of leucosin for this purpose. 

 The freshly ground meal was extracted with water, and, as the gummy 

 solution could not be filtered within a reasonable time, an equal volume of 

 saturated ammonium sulphate solution was added. The precipitate thus 

 produced was filtered out, dissolved in water, the solution filtered perfectly 

 clear, and the leucosin coagulated by heating the dilute solution to 65 in a 

 water-bath at 70. As the only other protein substance present in this solu- 

 tion was a relatively insignificant quantity of proteose, the product obtained 

 was practically free from any other protein. This coagulum was thoroughly 

 washed with hot water, in order to remove any admixed proteose, and dehy- 

 drated with absolute alcohol. The preparation formed a light white powder. 



Owing to the difficulty of preparing large quantities of this protein, which 

 occurs in very small quantity in the wheat kernel, we were limited in this 



1 Osborne, Journal American Chemical Society, 1895, xvn, p. 587. 



