label: L-seryl-[protein] + UDP-N-acetyl-alpha-D-glucosamine => 3-O-(N-acetyl-beta-D-glucosaminyl)-L-seryl-[protein] + UDP + H(+)
label_lc: l-seryl-[protein] + udp-n-acetyl-alpha-d-glucosamine => 3-o-(n-acetyl-beta-d-glucosaminyl)-l-seryl-[protein] + udp + h(+)