-!- Specific for (1->6)-alpha-D-glucans (dextrans) and, unlike cyclomaltodextrin glucanotransferase (EC 2.4.1.19), without activity toward (1->4)-alpha-D-glucans, such as amylose. -!- It also has no activity on oligosaccharides, such as amylopectin and pullulan, containing (1->6)-alpha-D-glucosidic linkages at branch points. -!- The enzyme from Bacillus circulans T-3040 has been shown to form cycloisomalto-oligosaccharides of three sizes (7, 8 and 9 glucose units). -!- It will also catalyze the disproportionation of two isomalto- oligosaccharides molecules to yield a series of isomalto- oligosachharides and the addition of D-glucose to cycloisomalto- oligosaccharides with ring opening to form isomalto-oligosaccharides.