The object of the present invention is to provide a polypeptide which can be used to produce a saccharide having the structure of cyclo{.fwdarw.6)-.alpha.-D-glucopyranosyl-(1.fwdarw.3)-.alpha.-D-glucopyr- anosyl-(1.fwdarw.6)-.alpha.-D-glucopyranosyl-(1.fwdarw.3)-.alpha.-D-glucop- yranosyl-(1.fwdarw.}, 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 .alpha.-1,6 glucosidic linkage as a linkage at the non-reducing end and the .alpha.-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 .alpha.-1,4 glucosidic linkage as a linkage at the non-reducing end by .alpha.-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.