Isopullulanase (EC 3.2.1.57) is an enzyme with systematic name pullulan 4-glucanohydrolase (isopanose-forming). This enzyme catalyses the following chemical reaction Isopullulanase (EC 3.2.1.57) is an enzyme with systematic name pullulan 4-glucanohydrolase (isopanose-forming). This enzyme catalyses the following chemical reaction The enzyme has no activity on starch.