LIPASE 475 



The fact that hydrolysis is slow at first and then suddenly in- 

 creases from 5 per cent after one day to 58 per cent after two 

 days and to 95 per cent after four days led Connstein to the 

 conclusion that for rapid hydrolysis a certain minimum amount 

 of free acid must be present, and it was found that when a 

 little free acid was added at the beginning, hydrolysis could 

 be completed within a few hours. Similar observations re- 

 garding the curve of the hydrolysis of fats during the ger- 

 mination of Ricinus seeds have been made by Deleano.* 



A simpler way of demonstrating the action of the lipase 

 of the castor-oil seed is to shell about 10 grams of the seeds 

 and to divide these into two portions A and B ; A is pounded 

 up in a mortar with 4 grams of castor oil and 5 c.c. of water, 

 while B is treated in the same way, 5 c.c. of N/io sulphuric 

 acid being used in place of the 5 c.c. of water. After about 

 an hour 25 c.c. of alcohol are added to each and the free acid 

 is titrated with N caustic soda in presence of a few drops of 

 phenolphthalein indicator. The quantity of acid developed in 

 B, after allowing for the 5 c.c. of acid originally added, will be 

 found to be much greater than that in A, showing that the 

 enzyme works more efficiently in an acid medium. 



Willstatter and Waldschmidt-Leitz f found that the dor- 

 mant seed of the castor oil contained a variety of lipase, 

 the activity of which was confined to P^ 47, no activity being 

 manifest at Pg 7. On the other hand, young seedlings were 

 found to contain a lipase which was active over a wide range 

 of hydrogen in concentration, from P^ 47 to Pj, 8. These 

 facts indicate two different varieties of lipase ; to the former 

 the name of spermatolipase has been given and to the latter, 

 blastolipase. Willstatter and Waldschmidt-Leitz suggest that 

 at the outset of germination proteolysis of the original enzyme 

 complex takes place and leads to the formation of blastolipase. 

 The amount of spermatolipase thus falls off as germination 

 proceeds, but there is no equivalent increase in the amount of 

 blastolipase, which, as a matter of fact, is unstable and is 



* Deleano : " Centrlbl. Bakt.," 1909, 24, 130. 



f Willstatter and Waldschmidt-Leitz : " Zeit. physiol. Chem.," 1924, 

 134, 161. 



