Kuniji Tanaka

Purification and properties of Arthrobacter ureafaciens inulase II

Abstract 1. 1. Arthrobacter ureafaciens inulase II, which converts inulin to di- d -fructofuranose 1,2′:2,3′ dianhydride (difructose anhydride III) and a small amount of oligosaccharides, was purified about 150-fold in the 43% yield from the cultured liquid of the bacteria by means of ammonium sulfate fractionation, followed by acetone fractionation and Sephadex G-100 gel filtration. A polarimetric measurement was carried out for the estimation of enzymatic activities. 2. 2. The purified enzyme was found to be homogeneous by polyacrylamide disc gel electrophoretic studies in support of an intramolecular transfructosidation reaction of the enzymatic reaction. The enzyme was optimally reactive at pH 6.0 and at 50 °C, and was stable within a broad pH range (pH 4 to 11) and below 50 °C. The activity was strongly inhibited by HgCl2.

Formation of di-d-fructofuranose 1,2′:2,3′ dianhydride from inulin by an extracellular inulase of Arthrobacter ureafaciens

Abstract 1. 1.|A strain of Arthrobacter ureafaciens isolated from soil was shown to produce an extracellular enzyme which degrades inulin to a difructose anhydride and a small amount of oligosaccharides. The products resulting from enzymic hydrolysis are different from those produced by the common inulase (β-2,1-fructan fructanohydrolase, EC 3.2.1.7) of the β-fructofuranosidase type. 2. 2.|Characterization and identification of the difructose anhydride indicated that it corresponds to di- d -fructofuranose 1,2′:2,3′ dianhydride, difructose anhydride III, described by Jackson and McDonald in 1931 ( Bur. Stand. J. Res. , 6 (1931) 709).

Purification of α-l-fucosidase of abalone livers

Abstract Purification of the α-fucosidase of abalone livers was attempted by fractionation with ammonium sulfate and subsequent treatments with DEAE-cellulose and IRC-50 resin. The estimations of recovery and purity of the enzyme were followed using p -nitrophenyl α- l -fucoside as substrate. The preparations obtained after treatments with DEAE-cellulose columns or IRC-50 resin were almost free of β- l -fucosidase, although they were contaminated with relatively large amounts of N -acetyl-β-glucosaminidase and N -acetyl-β-galactosa minidase. Both preparations were shown to contain two types of α- l -fucosidase different in the dependence of activity on pH and in substrate specificity. One was optimally active at around pH 5 on p -nitrophenyl α- l -fuicoside but not on the fucosidic linkages of porcine submaxillary mucin, while the other was optimally active around pH 2 on the synthetic substrate as well as on porcine submaxillary mucin. Evidence was obtained to show that the crude enzyme of the acetone-ether dry powder of the tissue homogenate used for the starting material contains a specific inhibitor for the enzyme component showing the highest activity at pH 2.

Hydrolysis of fucoidan by abalone liver α-L-fucosidase

cw-L-Fucosidase from abalone liver (Haliotis gigunteu Gmelin) was reported to hydrolyze methyl cY-L-fucoside and fucosidic linkages of fucoidan and blood-group substances [I] . However, this enzyme has been shown to be composed of two enzyme components [2]. One component acts on p-nitrophenyl a-L-fucoside as well as fucosidic linkages of porcine submaxillary mucin, and shows optimal activity at around pH 2 (pH 2-enzyme). The other component acts on the synthetic substrate, but not on the mucin, and shows highest activity at around pH 5 (pH 5-enzyme). On the other hand, a fucoidanase which shows hydrolytic activity toward fucoidan, but no activity toward p-nitrophenyl o-L-fucoside and blood-group A substance was reported from the livers of related species (IZ. rufescens and H. contgata) [3] . These previous studies suggest that cw-L-fucosidase of this genus is differentiated in the substrate specificity. The present paper reports on an exofucoidanase action of the pH 5-enzyme of H. gigm tea Gmelin.