Polypeptide having α-isomaltosylglucosaccharide synthase activity

Abstract

The object of the present invention is to provide a polypeptide which can be used to produce a saccharide having the structure of cyclo{→6)-α-D-glucopyranosyl-(1→3)-α-D-glucopyranosyl-(1→6)-α-D-glucopyranosyl-(1→3)-α-D-glucopyranosyl-(1→}, a DNA encoding the polypeptide, and uses thereof. The present invention solves the above object by establishing a polypeptide which has an enzymatic activity of forming a saccharide with a glucose polymerization degree of 3 or higher and bearing both the α-1,6 glucosidic linkage as a linkage at the non-reducing end and the α-1,4 glucosidic linkage other than the linkage at the non-reducing end from a saccharide with a glucose polymerization degree of 2 or higher and bearing the α-1,4 glucosidic linkage as a linkage at the non-reducing end by α-glucosyl transferring reaction without substantially increasing the reducing power, a DNA encoding the polypeptide, a replicable recombinant DNA comprising the DNA encoding the polypeptide and an autonomously replicable vector, a transformant constructed by introducing the recombinant DNA into an appropriate host, and uses thereof.