Gene cloning and characterization of a trehalose synthase from Corynebacterium glutamicum ATCC13032

초록

Trehalose synthase (TreS) is an enzyme which produces trehalose from maltose through intramolecular transglycosylation. In this study, a gene (cg2529) encoding for TreS from Corynebacterium glutamicum (CgTS) was cloned and expressed in Escherichia coli. The hexahistidinetagged CgTS showed an optimum temperature and pH of 35A degrees C and pH 7.0, respectively. This enzyme was not thermostable, but stable in a broad pH range from pH 5.0 to 8.5. Its activity slightly increased by 5 mM Mg2+ and Fe2+, while it was strongly inhibited by 5 mM sodium dodecyl sulfate (SDS). CgTS catalyzed the conversion from maltose into trehalose, and vice versa. Lowering reaction temperature by 5A degrees C from the optimum temperature significantly reduced hydrolysis activity to produce glucose as a by-product compared to transglycosylation activity to produce trehalose, leading to increase in the conversion yields from maltose into trehalose. Consequently, the maximum conversion yield by CgTS reached 69% at 25A degrees C after 9 hr of reaction.

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