Keratan-sulfate endo-1,4-ò-galactosidase (, endo-ò-galactosidase, keratan sulfate endogalactosidase, keratanase, keratan-sulfate 1,4-ò-<small>D</small>-galactanohydrolase) is an enzyme with systematic name keratan-sulfate 4-ò-<small>D</small>-galactanohydrolase. It catalyses endohydrolysis of (1âÂÂ4)-ò-<small>D</small>-galactosidic linkages in keratan sulfate.
It hydrolyses the 1,4-ò-<small>D</small>-galactosyl linkages adjacent to 1,3-N-acetyl-ñ-<small>D</small>-glucosaminyl residues.