Abstract
Inulinases (β-2, 1-fructan fructanohydrolase, EC 3.2.1.7) from yeast, fungi and higher plants are β-fructofuranosidases, which split off the terminal fructose units from the inulin molecule. However, considering the wide distribution of inulin and related substances as carbohydrate reserves in plant tissues, and their efficient degradation, the existence of other types of inulin-degrading enzymes could be expected. We have tried to isolate bacterial strains which produce such an enzyme. During the course of our investigation, we isolated a strain of Arthrobacter ureafaciens which produces a novel inulin-degrading enzyme [inulin fructotransferase (depolymerizing), EC 2.4.1.93]. Inulin f ructotransf erase acts on inulin to form difructose anhydride III through an intramolecular transfructosylation reaction. This paper describes the followings; 1) Enzymic reactions occurring in difructose anhydride metabolism. 2) Structures of difructose anhydrides. 3) Derivatives of dif ructose anhydride III.
