Sulfotransferase that utilizes 3'-phospho-5'-adenylyl sulfate (PAPS) as sulfonate donor to catalyze the transfer of sulfate to position 6 of the N-acetylgalactosamine (GalNAc) residue of chondroitin (PubMed:9714738, PubMed:9883891, PubMed:15215498). Chondroitin sulfate constitutes the predominant proteoglycan present in cartilage and is distributed on the surfaces of many cells and extracellular matrices (PubMed:9714738). Catalyzes with a lower efficiency the sulfation of Gal residues of keratan sulfate, another glycosaminoglycan (PubMed:9714738). Can also catalyze the sulfation of the Gal residues in sialyl N-acetyllactosamine (sialyl LacNAc) oligosaccharides (By similarity). May play a role in the maintenance of naive T-lymphocytes in the spleen (By similarity). n 3'-phosphoadenylyl sulfate + chondroitin beta-D-glucuronate = n adenosine 3',5'-bisphosphate + chondroitin 6'-sulfate + 2 H(+) 3'-phosphoadenylyl sulfate + keratan = adenosine 3',5'-bisphosphate + keratan 6'-sulfate. Widely expressed in adult tissues. Expressed in heart, placenta, skeletal muscle and pancreas. Also expressed in various immune tissues such as spleen, lymph node, thymus and appendix. N-glycosylated. The disease is caused by variants affecting the gene represented in this entry. Belongs to the sulfotransferase 1 family. Gal/GlcNAc/GalNAc subfamily.