REVERSIBLE ACTION OF LIPASE 13 



saccharose, starch and dextrins also are described. It is not 

 unlikely, as Maquenne has pointed out, that the nature of the 

 carbohydrate depends upon the kind of fat and its degree of 

 saturation. He considers that the saturated fatty acids con- 

 tribute in a much lesser degree to the formation of sugars than 

 do the unsaturated acids, and that the saturated fatty acids 

 are principally used for respiratory purposes. Agreement, 

 however, between the authorities in respect to this aspect of 

 the subject does not obtain. Ivanow considers that there is no 

 real difference between the saturated and unsaturated fatty 

 acids in their power to give origin to carbohydrates. The 

 difference in their amounts is due to the more rapid conversion 

 of the unsaturated variety. However this may be, the salient 

 feature in the germination of a fat-containing seed is the con- 

 version of the fat into carbohydrate, the reverse to what 

 obtains during the maturation of the seed. The change is 

 effected by the activity of lipase which hydrolyses the fat into 

 glycerol and fatty acid. 



The work of Ivanow has shown that lipase has a reversible 

 action, and the fact whether it hydrolyses or synthesizes fats 

 is merely a question of conditions, mainly the presence or 

 absence of water. The glycerol extract of a fat-containing 

 seed, which extract contains the lipase, mixed with oleic acid 

 will synthesize a fat : the addition of water will result in the 

 hydrolysis of this fat into glycerol and fatty acid. 



In the synthesis of fats, Ivanow considers that higher 

 saturated acids of the fatty series are the first to be formed 

 from the sugar, and these are converted into unsaturated acids 

 which combine with the glycerol to form the fat. 



With regard to the origin of glycerol, the chemical re- 

 lationship between this substance and glucose is so close as 

 to suggest at once the possible inter-relation of the two ; 

 further, glycerol may have an origin in respiratory processes 

 as is shown by the production of this substance during the 

 alcoholic fermentation of sugar. 



