Isolation of Streptomyces sp. Producing Glucose-tolerant β-Glucosidases and Properties of the Enzymes(Microbiology & Fermentation Industry)

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Streptomyces sp. No. 35, taxonomically closed to S.thermodiastaticus, was isolated from domestic soil. It showedβ-glucosidase activity only in the cells. The enzyme synthesis was induced by cellobiose. Repeated DEAE-Toyopearl chromatography of a sonic extract of the cells showed three activity peaks, F_1, F_2, and F_3, which were eluted in the relative amount of 50 : 50 : 1 in this order by an NaCl concentration gradient. The enzymes were purified to homogeneity. Molecular weights of F_1, F_2, and F_3 were 100,000, 105,000, and 130,000 by gel filtration, and 52,000, 50,000, and 52,000, respectively, by sodium dodecyl sulfate-polyacrylamide-gel electrophesis. F_1 and F_2 hydrolyzed PNP-β-glucoside and cellobiose nearly at the same rate, while F_3 hydrolyzed the former slightly. F_1 and F_2 were inhibited by glucose, giving Kis of 56 and 40 mM, respectively. On the other hand, F_3 was activated twofold by 0.1 M glucose and inhibited 50% by 1 M glucose. Xylose also similarly activated F_3. All the enzymes hadβ-galactosidase activities. Theβ-galactosidase activity of F_3 was not activated by any compounds tested, but rather inhibited by glucose and D-arabinose.
社団法人日本農芸化学会の論文
1991-04-23