Hydrolyzes pullulan efficiently but only a small amount of starch. Endohydrolysis of 1,4-alpha-glucosidic linkages in pullulan to form panose. Cleaves also (1-6)-alpha-glucosidic linkages to form maltotriose. Hydrolysis of pullulan to panose (6-alpha-D-glucosylmaltose). Binds 1 Ca(2+) ion per subunit. Monomer. Belongs to the glycosyl hydrolase 13 family.