Carbohydrate sulfotransferase 13 (CHST13)

Catalyzes the transfer of sulfate to position 4 of the N-acetylgalactosamine (GalNAc) residue of chondroitin. Chondroitin sulfate constitutes the predominant proteoglycan present in cartilage and is spread on the surfaces of cells and extracellular matrices.

Transfers sulfate into the C4 hydroxyl of beta1,4-linked GalNAc that is substituted with a beta-linked glucuronic acid in the C-3 hydroxyl. No activity toward dermatan.