﻿1903] 



EXPERIMENTAL STUDIES OA INULASE 



33 



III. One gram of Aspergillus powder was extracted for 

 twenty-four hours in 50^^ of water containing a little toluol. The 

 extract was filtered and added to a solution of \a^^^ of inulin in 

 40'''' of water and the resulting mixture made up to 100^^. Of 

 this solution 20^^ were added to each of five test tubes and three 

 drops of toluol added to each tube. Number 5 was then boiled. 

 All were corked and kept at the temperatures given below for six 

 hours, at the expiration of which all were boiled and 15^*^ from 

 each tube analysed for levulose with the results given below. 



No. 



Temperature 



Mgnis. of levulose 



I 

 2 



3 

 4 

 5 



40" 



50'' boiled 



42.2 



55-5 

 51.8 



19,9 



20.9 



In the first series of tests the optimum temperature was nearer 

 60"" than 50"", but in the second and third series it was nearer 

 50°- It is noticeable that in the first series of tests the enzyme 

 was evidently present in much larger quantity than in any of 

 the subsequent digestions. In order to discern whether or not 

 the difference in the effect of the temperature was due to a differ- 

 ence in the concentration of the enzyme the following trial was 

 made : 



IV. In flask A one gram of Aspergillus powder was extracted 

 in 50^^ of water plus toluol. In flask B 2.5^°^^ of Aspergillus 

 powder were extracted in the same quantity of water. Both 

 extracts were filtered and added to 75^^ of the same inulin solu- 

 tion; toluol was added to each, and each solution made up to 

 I 50''''- Two series of six test-tubes each were filled from the two 

 solutions, 25" being placed in each tube. The tests were kept 

 at the temperatures given below for six hours, then boiled, and 

 20'='' from each was analyzed for levulose. 



From the results detailed below it appears that the optimum 

 temperature for inulase lies very near to 55°. There is an indnia- 

 tion that in more concentrated solutions the optimum tempera- 

 ture is slightly higher. It is a well-known fact that the presence 



