Characterization of α-Glucosyltransferase from Pseudomonas mesoacidophila MX-45

概要

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α-Glucosyltransferase was purified from Pseudomonas mesoacidophila MX-45. The molecular weight was estimated to be 63,000 by SDS-PAGE, and the isoelectric point was pI 5.4. For enzyme activity based on sucrose decomposition, the optimum pH and the optimum temperature were pH 5.8 and 40℃, respectively. The ranges of stable pH and temperature were pH 5.1-6.7 and below 40℃, respectively. The purified enzyme of MX-45 converted sucrose into trehalulose (1-O-α-D-glucopyranosyl-D-fructose) and isomaltulose (palatinose, 6-O-α-D-glucopyranosyl-D-fructose) simultaneously, and the ratio of trehalulose to isomaltulose increased at lower reaction temperatures. Therefore, optimum conditions for trehalulose production were pH 5.5-6.5 at 20℃. The yield of trehalulose from sucrose (20-40% solution) was 91%. The K_m for sucrose was 19.2±3.3 mM estimated by the Hanes-Woolf plot. Product inhibition was observed, and the product inhibition constant was 0.17M. Hg^<2+>, Fe^<3+>, Cu^<2+>, Mg^<2+>, Ag^+, Pb^<2+>, glucono-1, 5-lactone, and Tris (hydroxymethyl) aminomethane inhibited the reaction.
社団法人日本農芸化学会の論文
1994-10-23