GO:0102167:   [protein]-3-O-(N-acetyl-D-glucosaminyl)-L-serine O-N-acetyl-alpha-D-glucosaminase activity
Catalysis of the reaction: H2O + an N-acetyl-alpha-D-glucosaminyl-L-serine-[glycoprotein] <=> N-acetyl-alpha-D-glucosaminide + a [protein]-L-serine