Glycoside Hydrolase Family 66. Glycoside Hydrolase Family 66 contains proteins characterized as cycloisomaltooligosaccharide glucanotransferase (CITase) and dextranases from a variety of bacteria. CITase cyclizes part of a (1-6)-alpha-D-glucan (dextrans) chain by formation of a (1-6)-alpha-D-glucosidic bond. Dextranases catalyze the endohydrolysis of (1-6)-alpha-D-glucosidic linkages in dextran. Some members contain Carbohydrate Binding Module 35 (CBM35) domains, either C-terminal or inserted in the domain or both.