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EXPERIMENTAL STUDIES ON INULASE. 



Arthur L. Dean. 



In 1888 J. Reynolds Green^ reported the discovery of an 

 inulin-splitting enzyme in the Jerusalem artichoke, Helianthus 

 tuberostis. The tubers were planted and allowed to grow until 

 the stems were about six inches above the ground. At that time 

 the tissues of the tubers were found to have become much altered, 

 being spongy in the middle part, although the outer part was 

 still firm and contained inulin. A glycerine extract of these 

 tubers was prepared and dialysed free from sugar. Such an 

 extract was found to have the power to change inulin to a redu- 

 cing sugar. Experiments were carried out in test-tubes and in 

 dialysing tubes, with the result that Green was able to establish 

 quite conclusively that the germinating artichoke contained an 

 enzyme able to cause the hydrolysis of inulin. To this enzyme 

 he gave the name '*inulase." It is evident from Green's descrip- 

 tion that the extracts obtained by him were not very active. This 

 he accounts for by supposing the enzyme to occur in very small 

 quantities. 



Some time before Green's paper appeared, Bourquelot had 

 observed that Aspergillus niger grew well in media in which 

 inulin was the only carbohydrate. Later, in 1893, he^ published 

 several short papers in which he recorded finding inulase in As- 

 per^lhis niger. The inulase was associated with several other 

 enzymes, but Bourquelot was convinced that the cleavage of inulin 

 was the function of a distinct ferment. In another paper^ he 

 compared the pnzymes of Penicillium gla7icum dind Aspergillus niger, 

 and notes the fact that inulase is present in the first-named fungus. 



^On the germination of the Jerusalem artichoke (^Helianthus tuberostis). Annals 

 of Botany i : 223. 1888. 



'Inulase et fermentation alcoholique indirecte de Tinuline. Compt. Rend. 116: 

 1 143. 1893. Also in Compt. Rend. Soc. Biol. IX. 5:481. 1893. Les ferments solu- 

 bles d V Aspergillus ni^er. Bull. Soc. MycoK France 9: 230. 1893, 



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3Remarques sur les ferments solubles secretes par V Aspergillus et le Penicillium. 

 Compt. Rend. Soc. Biol. IX. 5 : 653. 1893. 



24 [JANUARY 



