Glucuronylgalactosylproteoglycan 4-beta-N-acetylgalactosaminyltransferase (, N-acetylgalactosaminyltransferase I, glucuronylgalactosylproteoglycan beta-1,4-N-acetylgalactosaminyltransferase, uridine diphosphoacetylgalactosamine-chondroitin acetylgalactosaminyltransferase I, UDP-N-acetyl-D-galactosamine:D-glucuronyl-1,3-beta-D-galactosyl-proteoglycan beta-1,4-N-acetylgalactosaminyltransferase) is an enzyme with systematic name UDP-N-acetyl-D-galactosamine:D-glucuronyl-(1->3)-beta-D-galactosyl-proteoglycan 4-beta-N-acetylgalactosaminyltransferase. This enzyme catalyses the following chemical reaction
This enzyme requires Mn<sup>2+</sup>.