Phospho-N-acetylmuramoyl-pentapeptide-transferase (EC 2.7.8.13) (mraY) is a bacterial enzyme responsible for the formation of the first lipid intermediate of the cell wall peptidoglycan synthesis. It catalyses the formation of undecaprenyl-pyrophosphoryl-N-acetylmuramoyl-pentapeptide from UDP-MurNAc-pentapeptide and undecaprenyl-phosphate. It is an integral membrane protein with probably ten transmembrane domains. This domain is located at the end of the first cytoplasmic loop and the beginning of the second transmembrane domain.