Sulfotransferase that transfers sulfate from 3'-phosphoadenosine 5'-phosphosulfate (PAPS) to the C-6 hydroxyl group of the GalNAc 4-sulfate residue of chondroitin sulfate A and forms chondroitin sulfate E containing GlcA-GalNAc(4,6-SO(4)) repeating units. n 3'-phosphoadenylyl sulfate + dermatan 4'-sulfate = n adenosine 3',5'-bisphosphate + dermatan 4',6'-bissulfate + n H(+) n 3'-phosphoadenylyl sulfate + chondroitin 4'-sulfate = n adenosine 3',5'-bisphosphate + chondroitin 4',6'-bissulfate + n H(+) In contrast to the human protein, it does not transfer sulfate to the unique non-reducing terminal sequence GalNAc(4SO4)-GlcA(2SO4)-GalNAc(6SO4). Belongs to the sulfotransferase 1 family.