H. E. Woodman 233 



blood serum, colo.stnun and milk (•'>). The method depends on the be- 

 haviour of proteins in dilute ulkaline solution. When such solutions are 

 kept at 37° C, they suffer a progressive diminution in the value of their 

 optical rotatory power as a result of a keto-enol tautomerism of the 

 = CH — CO — groups in the protein complex. If the specific rotations 

 of the solution be plotted against the time in hours during which the 

 reaction has been allowed to proceed, then the readings fall on a perfectly 

 smooth curve. It is found that the rotation sinks rapidly at first, then 

 more slowly and subsequently after about 250 hours attains a practically 

 constant value. The process thus results in the partial racemisation of 

 the protein, and the graphs thus obtained are referred to as racemisation 

 curves. 



Since individual proteins display specific behaviour quantitatively 

 when racemised with dilute soda, it follows that the method may be 

 used to test the identity or non-identity of related proteins. Thus, if 

 two proteins are to be pronounced identical, then if racemised under 

 the same conditions, their solutions must show the same initial rotation, 

 the same final rotation and the same rate of diminution of rotation. 

 They must also continue to display identical optical behaviour if the 

 concentration of the alkah or protein in the solution is varied. On the 

 other hand, if two proteins are not identical, this will be revealed by their 

 possessing distinct sets of racemisation curves. 



In the investigation to be outlined in the present communication, 

 samples of gliadine and glutenine have been isolated from typical strong 

 and weak flours and have been investigated comparatively by means 

 of the racemisation method. The results obtained are very suggestive 

 in relation to their bearing on the existing ideas of flour strength, since 

 it has been shown that whereas the gliadines from weak and strong 

 flours are identical proteins, yet the glutenines prepared from the same 

 sources appear to be two distinct chemical individuals. 



Preparation of Proteins. 



1. Gliadine and glutenine from strony flour. 



The flour used for this purpose was a typically strong flour milled 

 exclusively from Northern Manitoba Wheat. The method used for the 

 isolation of the proteins was in its essentials the same as that described 

 by Osborne (fi). The bulk of the starch and soluble constituents was 

 removed by enclosing the flour in a muslin bag and kneading the material 

 in a stream of running water, the process being completed by thoroughly 



