Lumped glycosyltransferase reactions group O:21: galactosyltransferase, acetyl-galactosaminyltransferase, acetyl-glucosaminyltransferase
uacgam_c + 2.0 udpgal_c + udpacgal_c + udcdpgalnac_c ⇌ 4.0 udp_c + udcdpgalnac_b1_3_gal_a1_4_gal_b1_3_galnac_a1_3_glcnac_c