alpha-1,6-mannosylglycoprotein 4-beta-N-acetylglucosaminyltransferase activity
UDP-N-acetyl-D-glucosamine:2,6-bis(N-acetyl-beta-D-glucosaminyl)-alpha-D-mannosyl-glycoprotein 4-beta-N-acetyl-D-glucosaminyltransferase activity