Enables N-acetylgalactosaminyl-proteoglycan 3-beta-glucuronosyltransferase activity and glucuronosyl-N-acetylgalactosaminyl-proteoglycan 4-beta-N-acetylgalactosaminyltransferase activity. Involved in chondroitin sulfate biosynthetic process. Predicted to be located in Golgi membrane. [provided by Alliance of Genome Resources, Apr 2022]