PGM3 (phosphoglucomutase 3), also known as PAGM (phosphoacetylglucosamine mutase) and AGM1 (N-acetylglucosamine-phosphate mutase), is an essential enzyme found in eukaryotes that reversibly catalyzes the conversion of GlcNAc-6-phosphate into GlcNAc-1-phosphate as part of the UDP-N-acetylglucosamine (UDP-GlcNAc) biosynthetic pathway. UDP-GlcNAc is an essential metabolite that serves as the biosynthetic precursor of many glycoproteins and mucopolysaccharides. AGM1 is a member of the alpha-D-phosphohexomutase superfamily, which catalyzes the intramolecular phosphoryl transfer of sugar substrates. The alpha-D-phosphohexomutases have four domains with a centrally located active site formed by four loops, one from each domain. All four domains are included in this alignment model.