TreX from Sulfolobus solfataricus ATCC 35092 Displays Isoamylase and 4-α-Glucanotransferase Activities

Abstract

A treX in the trehalose biosynthesis gene cluster of Sulfolobus solfataricus ATCC 35092 has been reported to produce TreX, which hydrolyzes the α-1,6-branch portion of amylopectin and glycogen. TreX exhibited 4-α-D-glucan transferase activity, catalyzing the transfer of α-1,4-glucan oligosaccharides from one molecule to another in the case of linear maltooligosaccharides (G3–G7), and it produced cyclic glucans from amylopectin and amylose like 4-α-glucanotransferase. These results suggest that TreX is a novel isoamylase possessing the properties of 4-α-glucanotransferase.