ACTION OF THE ENZYMES, 153 



thetic action upon any mixture of fat, fatty acid, and alcohol 

 is dependent solely upon the relative amounts of these sub- 

 stances present. Speaking broadly, the lipase will analyze 

 fat whenever this substance is present in excess, while it will 

 synthesize it if the fatty acid and alcohol are in excess, and 

 it will do one or the other of these until equilibrium has been 

 established. 



HANRIOT worked not with ethyl buytrate but with mono- 

 butyrin, which under the influence of lipase is split into 

 glycerine and butyric acid. When, under proper external 

 conditions, lipase is added to a mixture of glycerine and 

 butyric acid, monobutyrin is produced, as HANRIOT was 

 able to show by isolation of that compound. 



The synthesis of chemically much more complicated esters 

 than ethyl butyrate can, however, be brought about through 

 lipase. With the lipase obtained from the castor-bean 

 TAYLOR l succeeded in synthesizing triolein from a mixture of 

 oleic acid and glycerine. Since this same ferment is un- 

 able to split triolein and other fats completely, the reaction 

 coming to a standstill when some 75 to 90 percent of the 

 original fat has been broken up into glycerine and oleic acid, 

 the conclusion seems to be justified that the lipase obtained 

 from this source is also able to catalyze both the analysis and 

 the synthesis of fats in a way similar to that described in 

 KASTLE and LOEVENHART'S experiments. 



12. Sucrase (invertase, invertin) is a ferment which is 

 characterized by its power of splitting the disaccharide, cane- 

 sugar (sucrose) into a mixture of two monosaccharides. The 

 monosaccharides produced are known as "invert-sugar," 

 and consist of a mixture of equal parts of dextrose and laevu- 

 lose. The change which cane-sugar undergoes under the 

 influence of sucrase is expressed by the following formula: 



Sucrose Water Dextrose Lsevulose 



1 TAYLOR: University of California Publications, Pathology, 1904, 

 I, p. 33. 



