PANCREATIC RENNIN. 487 



explains in part why the decomposition of proteins in vitro is slower than 

 in the digestive tract, where the decomposition products are removed 

 by absorption. On following the changes in the optical behavior during 

 the enzymotic cleavage of polypeptides one can, as ABDERHALDEN with 

 KOELKER and BRAHM l have shown, determine at which point the enzyme 

 first applies its action in the cleavage of a tripeptide. We cannot enter 

 into further detail as regard this and the other related behaviors. 



Pancreatic rennin is an enzyme found in the gland and in the juice, 

 which coagulates neutral or alkaline milk (KUHNE and ROBERTS and 

 others). This enzyme, according to PAWLOW'S school, is identical with 

 trypsin. The similarity of action of these two enzymes and the fact that 

 both are activated simultaneously from the zymogen's by enterokinase or 

 lime salts (DELEZENNE, WOHLGEMUTH 2 ) seem to point to this identity. 

 On the other hand the optimum of the enzyme action for the pancreatic 

 rennin is 60-65 C. (VERNON), which is much higher than for the trypsin,, 

 and GLAESSNER and POPPER 3 have also observed a case where the human 

 pancreatic juice contained no rennin enzyme. 



According to HALLIBURTON and BRODIE * casein is converted by the pancreatic 

 juice of the dog into " pancreatic " casein, a substance which, in regard to solubility, 

 stands to a certain extent between casein and paracasein (see Chapter XIV), 

 and which is converted into paracasein by rennin. Further investigations on 

 the action of this enzyme upon milk and especially upon pure casein solutions are 

 very desirable. 



The property of pancreatic juice of giving plastein precipitates is just as 

 inexplicable as in the case of the gastric juice and other enzyme solutions. 



Pancreatic Calculi. The concrement from a cystic enlargement of WIRSUJJG'S 

 duct in a man, as analyzed by BALDONI, contained in 1000 parts as follows: 

 Water 34.4, ash 126.7, protein substances 34.9, free fatty acids 133, neutral fats 

 124, cholesterin 70.9, soaps and pigment 499.1, parts. SCHEUNERT and BERG- 

 HOLZ 5 have reported a pancreatic calculi in the ox. 



Besides the enzymes which have been discussed in connection with 

 the pancreatic juice, the gland also contains others, among which can be 

 mentioned the enzyme which, according to STOKLASA and his collabora- 

 tors, occurs chiefly in organs and tissues and which decomposes sugar 

 into alcohol and carbon dioxide, like zymase. Opinions as to the 

 importance of the pancreas for glycolysis are diverse, and we therefore 



1 Abderhalden with Koelker, Zeitschr. f. physiol. Chem., 54 and 55; with Brahm, 

 ibid., 57. 



2 Kiihne and Roberts, Maly's Jahresber., 9; see also Edkins, Journ. of Physiol., 12 

 (literature); Delezenne, Compt. rend. soc. biol., 62 and 63; Wohlgemuth, Bioch. 

 Zeitschr., 2. 



3 Vernon, Journ. of Physiol., 12; Glaessner and Popper, Deutsch. Arch. f. klin. 

 Med., 94. 



4 Journ. of Physiol., 20. 



5 Baldoni, Maly's Jahresb., 29, 353; Scheunert and Bergholz, Zeitschr. f. physioL 

 Chem., 52. 



