In addition to catalyzing the synthesis of dextran from sucrose as a primary reaction, dextransucrase also catalyzes the transfer of glucose from sucrose to other carbohydrates that are present or are added to the reaction digest. We have synthesized new glucans having new structures and new characteristics, by transferring D-glucose of sucrose to $alpha$-cellulose and by using the constitutive dextransucrase obtained from Leuconostoc mesenteroides B-742CBM. The final reaction products were composed of soluble- and insoluble-glucans. The yields of soluble- and insoluble-glucans were theoretically 21% $pm$ 2.2 and 68% $pm$ 5.1, respectively. The remainder of the reaction products was recovered as a mixture of olgiosaccharides that could not be precipitated by 67%(v/v) ethanol. Treating the modified glucans with endo-dextranase and/or cellulase, oligosaccharides were produced that were not formed from the hydrolysis of native cellulose or B-742CBM dextran. The modification of the cellulose was confirmed by methylation and acid hydrolysis of the soluble-and insoluble-glucan. Both (1->4) and(1->6) glycosidic linkages were found in both of the glucans.