ROLE OF BILE IN LIPID ABSORPTION 69 



enzyme in extracts from the intestine, pancreas, kidney, bones, or in the 

 liver and blood of several species of animals examined (including human 

 blood). However, Patwardhan 397 reported phytase activity in the intes- 

 tine of the rat; little if any activity was noted in the intestine of the rabbit 

 and guinea pig, or in the bone extracts of any animals studied. 



In the later studies of Rapoport et al., m phytase was found in the plasma 

 of fowl (goose, pigeon, chicken, and duck), snakes (moccasin and brown 

 water-snakes), fishes (bullhead and black bass), the turtle, and the bull- 

 frog. The presence of this enzyme in the plasma of man was so slight as to 

 be questionable, while none was found in guinea pig, beef, or calf blood. 

 Phytase was found in the erythrocytes only in those cases in which phytic 

 acid was present, namely, goose, chicken, pigeon, and turtle. In these 

 cases, it occurred in an extremely constant amount, in contradistinction to 

 the wide variations of the enzyme in the various plasma samples. On the 

 basis of the properties of the cell and the plasma phytase, Rapoport ct al. 3 ' M 

 concluded that they are one and the same enzyme. 



Phytase is a separate entity which is distinct in nature from the other 

 phosphatases. The addition of the end-products, i.e., inositol and phos- 

 phoric acid, has little effect on the activity of the enzyme, but it is inhibited 

 by fluoride ions and, to a greater extent, by oxalate ions. Although Pat- 

 wardhan 397 reported activation of the rat intestinal phytase by magnesium 

 ions, Rapoport et aZ. 390 could demonstrate no increase in activity on the 

 addition of such ions. When phytase was heated at 50°C. for ten minutes, 

 its activity was depressed, while the enzyme was almost completely de- 

 stroyed (87%) when subjected to a temperature of 60°C. The action of 

 phytase was highest at a temperature of 37.5°C. The level for optimum 

 />H was found to be G.G for plasma phytase from the goose, pigeon, turtle, 

 and frog, and 7.0 for that from the chicken. 390 



3. The Role of Bile in Lipid Absorption 



While bile contains no lipases, it does play an essential role in the ab- 

 sorption of neutral fats and in that of other lipids. In obstructive jaun- 

 dice, under which condition bile fails to reach the intestine, there is an im- 

 mediate marked decrease in the extent of lipid absorption. However, this 

 drop in utilization may not be confined solely to the fats and other lipids, 

 but may also be reflected in the case of proteins and carbohydrates. This 

 latter effect is to be traced only indirectly to the failure of fat to be absorbed. 

 It is believed that the presence of the unabsorbed fat in the gut contents 



2; ' 7 V. N. Patwardhan, Biochem J., SI, 560-564 (1937). 



