PANCREATIC DIGESTION IQI 



name implies, its activity is confined to the starches, and the products 

 of its amylolytic action are dextrins and sugar. The sugar is principally 

 maltose and this, by the further action of an inverting enzyme (maltase) , 

 is transformed into glucose. 



It is possible that the saliva as a digestive fluid is not absolutely 

 essential. The salivary amylase (ptyalin) is destroyed by the hydro- 

 chloric acid of the gastric juice and is therefore inactive when the chyme 

 reaches the intestine. Should undigested starch be present at this 

 point, however, it would be quickly transformed by the active pancreatic 

 amylase. This enzyme is not present in the pancreatic juice of infants 

 during the first few weeks of life, thus showing very clearly that a starchy 

 diet is not normal for this period. 



The pronounced influence of electrolytes upon the action of pancrea- 

 tic amylase and other amylases has been demonstrated many times. 1 

 In fact the removal of electrolytes from pancreatic juice by dialysis 

 yields a juice which possesses no power to split starch. It also appears 

 that the Cl, Br and NOs ions have an important stimulating action*/ 

 upon the amylases. 2 



It has been shown that pancreatic amylase will digest raw starch. 

 The raw starch of corn and wheat may be completely digested and 

 absorbed by normal adults whereas the raw potato starch is about 

 80 per cent available. 3 



The extent to which amylase is present in the feces has been taken as 

 the index of pancreatic activity. 



The third enzyme of the pancreatic juice is called pancreatic lipase 

 (steapsin) and is a fat-splitting enzyme. It has the power of splitting 

 the neutral fats of the food by hydrolysis, into fatty acid and glycerol. 

 A typical reaction would be as follows: 



Palmitin. Palmitic acid. Glycerol. 



Recent researches make it probable that fats undergo saponifica- 

 tion prior to their absorption. The fatty acids formed unite with the 

 alkalis of the pancreatic juice and intestinal secretion to form soluble 

 soaps which are readily absorbed. It was formerly believed that the 

 fats could also be absorbed hi emulsion a condition promoted by the 

 presence of the soluble soaps. After absorption the fatty acids are 

 resynthesized to form neutral fats with glycerol. 



Bloor 4 has reported experiments which "make it extremely probable 



1 For the literature see Kendall and Sherman: Jour. Am. Chem. Soc., 32, 1087, 1910. 



2 Wohlgemuth : Biochem. Zeit., 9, 10, 1908; and Kendall and Sherman: Jour. Am. Chem. 

 Soc., 32, 1087, 1910. Bierry: Biochem. Zeit., 40, 357, 1912. Rockwood: Jour. Am. 

 Chem. Soc., 41, 228, 1919. 



3 Langworthy and Deuel: Jour. Biol. Chem., 42, 27, 1920. 



4 Bloor: Jour. Biol. Chem., 15, 105, 1913. 



