﻿34 



BOTANICAL GAZETTE 



[JANUARY 



Series A. — Extract from i^"^ Aspergillus powder, 



Temperature 



Mgiiis. of levulose 



40° 





22.5 



50° 





27. I 



55° 





29.3 



60" 





25.7 



65" 





14.7 



55° 



boiled 



II. 7 



Series B. — Extract from 2.5^"^^ Aspergillus powder. 



Temperature 



Mgms. of levulose 



40^ 



55' boiled 



59 

 70 



74 

 71 

 44 

 33 



4 



6 



9 



9 

 2 



of foreign substances — inorganic salts, proteids, etc. — in the 

 solution in which an enzyme is acting will tend to raise the tem- 

 perature at which destruction of the enzyme takes place, and in 

 many cases to raise its optimum working temperature.^ It will 

 be of interest to discover whether or not inulase prepared by a 

 more careful method, by which the bulk of all impurities is elimi- 

 nated, will show a much lower optimum temperature and range 

 itself with those enzymes which act best at about 40° C. 



SUMMARY. 



1. In confirmation of the results of Bourquelot, inulase was 

 found in the fungi Aspergillus niger and Penicillium glmicum. 



2. The inulase of these fungi does not pass into the culture 

 medium; it is therefore an endo-enzyme. 



3. The preparations of inulase from Aspergillus and Peni- 

 cillium show similar variations in activity due to changes in 

 the reaction of the medium. The enzyme acts most vigorously 

 in ^ medium containing 0,0001 normal acid (H^SO^'); greater 



8Cf. Chittenden: On digestive proteolysis, pp. 18, 19. New Haven. i895- 

 Pugliese: Ueber den Einfluss der Erwarmung auf diastatische Fermente. Archiv 

 Gesamm. Physiol. 6g : 115. 1898. 



V 



