Hydrolyses the 1,4-beta-D-galactosyl linkages adjacent to 1,3-N-acetyl-alpha-D-glucosaminyl residues. Also acts on some non-sulfated oligosaccharides, but only acts on blood group substances when the 1,2-linked fucosyl residues have been removed (cf. EC 3.2.1.102 blood-group-substance endo-1,4-beta-galactosidase).
Endo-beta-galactosidase of Escherichia freundii. Purification and endoglycosidic action on keratan sulfates, oligosaccharides, and blood group active glycoprotein.