Predicted to enable glucuronosyl-N-acetylgalactosaminyl-proteoglycan 4-beta-N-acetylgalactosaminyltransferase activity. Predicted to be involved in chondroitin sulfate biosynthetic process. Predicted to be located in Golgi cisterna membrane. Is expressed in several structures, including brain; cranial cartilage; mesoderm; proctodeum; and shield. Orthologous to human CHPF (chondroitin polymerizing factor).