Cell wall formation. Adds enolpyruvyl to UDP-N-acetylglucosamine (PubMed:20392080, PubMed:22378791). Target for the antibiotic fosfomycin. phosphoenolpyruvate + UDP-N-acetyl-alpha-D-glucosamine = phosphate + UDP-N-acetyl-3-O-(1-carboxyvinyl)-alpha-D-glucosamine In vitro inhibited by covalent binding of fosfomycin and the fungal product terreic acid in the presence of substrate UDP-N-acetylglucosamine, with an inactivation rate constant of 130 M(-1)sec(-1) for terreic acid. Cell wall biogenesis; peptidoglycan biosynthesis. Belongs to the EPSP synthase family. MurA subfamily.