COMPOSITION OF FOOD AND ACTION OF ENZYMES. 



745 



made or unmade, that is to say, it constitutes a reversible reac- 

 tion. In a mixture of bile salts and lipase, for example, the bile 

 salts may be removed by dialysis. In activation, on the contrary, 

 we have an irreversible reaction — the active trypsin cannot be 

 changed to the inactive trypsinogen.* 



PARTIAL LIST OF THE ENZYMES CONCERNED IN THE PROC- 

 ESSES OF DIGESTION AND NUTRITION. 



Converts starch to sugar 

 (maltose) . 



Converts starch to sugar 

 (maltose) . 



Converts glycogen to dex- 

 trose. 



Converts glycogen to dex- 

 trose. 



Converts cane-sugar to 

 dextrose and levulose. 



Converts maltose to dex- 

 trose. 



Converts lactose to dex- 

 trose and galactose. 



Splits and oxidizes dex- 

 trose. 



Sphts neutral fats to fatty 

 acids and glycerin. 



Converts proteins to pep- 

 tones and proteoses. 



SpUts proteins into their 

 constituent amino-acids. 



SpUts peptones and pro- 

 teoses into their con- 

 stituent amino-acids. 



SpUts proteins into nitrog- 

 enous bases and amino- 

 bodies. 



Spht nucleic acid with for- 

 mation of purin bases, 

 etc. 



Converts guanin to xan- 

 thin by splitting off an 

 NHo group as ammonia 

 (NH3). 



Converts adenin to hypo- 

 xanthin by splitting off 

 an NH2 group as am- 

 monia (NHs). 



SpUts off the NH2 group 

 from the amino-acids 

 with the formation of 

 non-nitrogenous organic 

 acids. 



* Consult Bayliss, "The Nature of Enzyme Action" (series of monographs 

 on Biochemistry), London, 1908. 



