Isolated from?Mycobacterium tuberculosis?and?Mycobacterium smegmatis. This enzyme catalyses the synthesis of monotrans,octacis-decaprenyl-N-acetyl-¦Á-D-glucosaminyl diphosphate (mycobacterial lipid I), an essential lipid intermediate for the biosynthesis of various bacterial cell envelope components.?cf. EC?2.7.8.33, UDP-GlcNAc:undecaprenyl-phosphate GlcNAc-1-phosphate transferase.