A STUDY OF THE ACTION OF ACID AND ALKALI ON 



GLUTEN. 



Bv L. J. HENDERSON, EDWIN J. COHN,* P. H. CATHCART,* 



J. D. WACHMAN,* and W. O. FENN.* 



{From the Wolcoit Gibhs Memorial Laboratory, Harvard University, Cambridge, in 



Collaboration with the Division of Food and Nutrition, Medical 



Department, U. S. Army.) 



(Received for publication, January 7, 1919.) 



The problem of the acid-base equilibrium in systems containing pro- 

 tein substances and electrolytes has often been obscured by super- 

 ficial interpretations of experimental results and, in recent investiga- 

 tions, by undue emphasis upon the colloidal aspects of the phenomena. 

 Nevertheless, it has always remained certain that proteins, as am- 

 photeric substances, must under all circumstances, except when pure 

 at the isoelectric point, combine chemically with acids or bases. 

 Moreover, the simple relationships involved in such equilibria are the 

 most important factors in determining the properties of the systems. 

 This conception of the behavior of protein systems has recently been 

 reaffirmed and amphfied by Sorensen and his associates,^ and by Loeb.^ 



The studies which are reported in the present paper point in this 

 same direction. Our experiments have been made with gluten, in 

 some respects not the most favorable material for investigation, be- 

 cause it contains two distinct proteins, because it has not been highly 

 purified from electrolytes, and because it possesses marked colloidal 

 properties. In spite of these obstacles, which must therefore be less 

 important than they seem, the results indicate a simple chemical 

 interpretation of the phenomena. 



This research was undertaken under the pressure of war time prac- 

 tical interests, for the purpose of explaining the technology of bread 



* Lieutenant, Sanitary Corps, U. S. Army. 



^ Sorensen and others, Compt. rend. trav. Lab. Carlsberg, 1917, xii. 

 2 Loeb, J., /. Biol. Chem., 1917, xxxi, 343; 1918, xxxiii, 531; 1918, xxxiv, 77, 395, 

 489; 1918, xxxv, 497; /. Gen. Physiol, 1918-19, i, 39. 



459 



