Catalyzes the last two sequential reactions in the de novo biosynthetic pathway for UDP-N-acetyl-glucosamine (UDP-GlcNAc). Responsible for the acetylation of GlcN-1-P to GlcNAc-1-P, and for the uridyl transfer from UTP to GlcNAc-1-P, to produce UDP-GlcNAc and pyrophosphate. Also catalyzes the reverse reaction, i.e. the cleavage of UDP-GlcNAc with pyrophosphate to form UTP and GlcNAc-1-P. To a lesser extent, is also able to use dUTP or dTTP as the nucleotide substrate, but not CTP, ATP or GTP. H(+) + N-acetyl-alpha-D-glucosamine 1-phosphate + UTP = diphosphate + UDP-N-acetyl-alpha-D-glucosamine acetyl-CoA + alpha-D-glucosamine 1-phosphate = CoA + H(+) + N-acetyl-alpha-D-glucosamine 1-phosphate Optimum pH is 7.5. Optimum temperature is 50-60 degrees Celsius. Activity is 22% lower at 60 degrees Celsius and 60% lower at 100 degrees. Thermostable. Nucleotide-sugar biosynthesis; UDP-N-acetyl-alpha-D-glucosamine biosynthesis; N-acetyl-alpha-D-glucosamine 1-phosphate from alpha-D-glucosamine 6-phosphate (route II): step 2/2. Nucleotide-sugar biosynthesis; UDP-N-acetyl-alpha-D-glucosamine biosynthesis; UDP-N-acetyl-alpha-D-glucosamine from N-acetyl-alpha-D-glucosamine 1-phosphate: step 1/1. In the N-terminal section; belongs to the N-acetylglucosamine-1-phosphate uridyltransferase family. In the C-terminal section; belongs to the transferase hexapeptide repeat family.