Is able to efficiently hydrolyze alpha-, beta-, and gamma-cyclomaltodextrins and linear maltooligosaccharides, to glucose and maltose, by decycling cyclodextrins and liberating glucose from the reducing end of the molecules. Shows a very weak activity on starch and pullulan. Cannot hydrolyze maltose or disaccharides with various types of alpha-links. Is not active against beta-glycosidic bonds of poly-, oligo-, and disaccharides. cyclomaltodextrin + H2O = linear maltodextrin Addition of 1 mM MnCl(2), NiCl(2), CoCl(2), ZnCl(2), CuCl(2), or 0.1 mM HgCl(2) inhibits the enzyme activity to 0-6%. Activity is increased in vitro upon addition of CaCl(2), DTT (relative activity 147%), KCl (180%), or EDTA (180%), as well as after heating of the enzyme. Is not inhibited by acarbose, a potent alpha-amylase and alpha-glucosidase inhibitor; on the contrary, acarbose is degraded quantitatively by AglB, yielding glucose. Optimum pH is 6.5 with pNP-alpha-D-maltoside as substrate. Optimum temperature is 85 degrees Celsius with pNP-alpha-D-maltoside as substrate. Remains stable after preincubation for various periods up to 48 hours at temperatures between 50 and 90 degrees Celsius, pH 6.5. The half-life of the enzyme at 95 degrees Celsius is 2 hours. Forms a mixture of homotetramers, homooctamers, and larger homooligomers. Belongs to the glycosyl hydrolase 13 family.