Galactan endo-beta-1,3-galactanase (, endo-beta-1,3-galactanase) is an enzyme with systematic name arabinogalactan 3-beta-D-galactanohydrolase. This enzyme catalyses the following chemical reaction
The enzyme from the fungus Flammulina velutipes (winter mushroom) hydrolyses the beta(1->3) bonds found in type II plant arabinogalactans.