Endohydrolysis of (1->4)-alpha-D-glucosidic linkages in polysaccharides containing three or more (1->4)-alpha-linked D-glucose units. Hydrolysis of (1->6)-alpha-D-glucosidic linkages in pullulan, amylopectin and glycogen, and in the alpha- and beta-limit dextrins of amylopectin and glycogen. Belongs to the glycosyl hydrolase 13 family. Contaminating sequence. Vector contamination at the C-terminus, a segment of 9 residues, which seems to originate from a puc-type vector.