UDP-N-acetylglucosamine enolpyruvyl transferase (or MurA) is an enzyme that catalyzes the first committed step in peptidoglycan biosynthesis, namely the ligation of phosphoenolpyruvate (PEP) to the 3'-hydroxyl group of UDP-N-acetylglucosamine. This pyruvate moiety provides the linker that bridges the glycan and peptide portion of peptidoglycan.
The enzyme is inhibited by the antibiotic fosfomycin, which covalently modifies an active site cysteine residue.