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