Purification and Properties of a Novel Enzyme, Trehalose Synthase, from Pimelobacter sp. R48;

Abstract

A novel enzyme, trehalose synthase, was purified from a cell-free extract of Pimelobacter sp. R48 to an electrophoretically homogeneous state by successive chromatographies on DEA E-Toy opearl 650, Butyl-Toyopearl 650, and Mono Q HR5/5 columns. The molecular weight of the enzyme was estimated to be 62,000 by SDS–polyacrylamide gel electrophoresis, and the enzyme had a pI of 4.6 by gel isoelectrofocusing. The enzyme catalyzed the conversion of maltose into trehalose by intramolecular transglucosylation. The enzyme also converted trehalose into maltose but was inactive on other saccharides. The N-terminal amino acid of the enzyme was serine. The optimum pH and temperature were pH 7.5 and 20°C, respectively. The enzyme was stable in the range of pH 6.0–9.0 and up to 30°C for 60 min. The rate of conversion of maltose into trehalose was independent of the maltose concentration. The maximum yield of trehalose from maltose were 81.8%, 80.9%, and 76.7% at 5, 15, and 25°C, respectively. The activity was inhibited by Cu2+, Hg2+, Ni2+, Zn2+, and Tris. © 1996, Taylor & Francis Group, LLC. All rights reserved.