Abstract: A polypeptide of keratan sulfate 6-sulfotransferase having the following physicochemical properties:1 action: a sulfate group is transferred from a sulfate group donor to the hydroxyl group at C-6 position of galactose residue of keratan sulfate;2 substrate specificity: a sulfate group is not substantially transferred to chondroitin, chondroitin sulfate A, chondroitin sulfate C, dermatan sulfate and CDSNS-heparin;3 optimum pH: 6.2 to 6.54 activation: an activity is increased by Mn.sup.2+ or Ca.sup.2+ ;5 Km value for 3'-phosphoadenosine 5'-phosphosulfate: about 2.times.10.sup.-7 M; anda DNA coding for the polypeptide.