Cell wall formation. Adds enolpyruvyl to UDP-N-acetylglucosamine. Target for the antibiotic phosphomycin. phosphoenolpyruvate + UDP-N-acetyl-alpha-D-glucosamine = phosphate + UDP-N-acetyl-3-O-(1-carboxyvinyl)-alpha-D-glucosamine Cell wall biogenesis; peptidoglycan biosynthesis. Belongs to the EPSP synthase family. MurA subfamily.