INDIVIDUALITY OF TRYPSIN 43 



Tissues, p. 501) discussed their probable relation with the 

 genesis of the once celebrated freighting -theory (in accord- 

 ance with which the pancreas was freighted with digestive 

 ferment from the spleen). 



Even trypsin itself seems to belong to the group of acti- 

 vators of trypsinogen ; at any rate when the least amount of 

 trypsin is introduced into an inactive solution of the ferment 

 it is spontaneously activated. 



Individuality of Trypsin. Question has arisen whether 

 the digestive pancreatic ferment is chemically one single sub- 

 stance. L. Pollack has asserted that besides the trypsin 

 there is a mucin digesting ferment, " glutinase," in the pan- 

 creatic juice ; Vernon has accepted the existence of a peptone- 

 siplitting ferment ("pancreatic erepsin"). Other investiga- 

 tions rather favor the idea of the individuality of the protein- 

 digestive ferment of the pancreas. For example, the expla- 

 nation of the observed fact that trypsin, first acidulated with 

 hydrochloric acid and then neutralized, will freely digest 

 gelatin but no other proteins is to be found in the fact that in 

 highly alkaline conditions it digests all proteins but on addi- 

 tion of acid digests only gelatine; if, thereafter, alkali be 

 added the normal digestive properties recur. 21 In a recent 

 study K. Glassner and A. Stauber have again asserted the 

 existence of an erepsin in the pancreatic fluid along with 

 trypsin. 22 



Doubtless the activity of trypsin is influenced very 

 largely by the ions present in the solution. A dialysed solu- 

 tion of trypsin, for instance, shows diminished activity ; but 



21 H. M. Vernon, Jour, of Physiol., 30, 330, 1903; K. Mays (Laboratory 

 of A. Kossel), Zeitschr. f. physiol. Chem., 38, 502, 1903; 49, 124, 188, 1906; 

 VY. M. Bayliss and E. H. Starling, Journ. of Physiol., SO, 61, 1903; L. Pollack, 

 Hofmeister's Beitr., 6, 95, 1905; Arch. f. Verdauungskr., 11, 362, 1905; M. 

 Ehrenreich, Arch. f. Verdauungskr., 11, 261, 364, 1905; A. Ascoli and B. 

 Neppi, Zeitschr. f. physiol. Chem., 56, 135, 1908; G. Schaeffer and E. F. 

 Terroine, Journ. de Physiol., 12, 884, 906, 1910. 



21 K. Glassner and A. Stauber (E. Freund's Lab.), Biochem. Zeitschr., 25, 

 204, 1910. 



