CGA has typical kinetic properties for a glucoamylase, but this bacterial enzyme had higher isomaltose-hydrolyzing activity than other eukaryotic glucoamylases. Hydrolysis of terminal (1->4)-linked alpha-D-glucose residues successively from non-reducing ends of the chains with release of beta-D-glucose. High activity towards 1,6-glycosidic bonds. Belongs to the glycosyl hydrolase 15 family.