Controls the flux of glucose into the hexosamine pathway. Most likely involved in regulating the availability of precursors for N- and O-linked glycosylation of proteins. Regulates the circadian expression of clock genes ARNTL/BMAL1 and CRY1 (PubMed:23395176). Has a role in fine tuning the metabolic fluctuations of cytosolic UDP-GlcNAc and its effects on hyaluronan synthesis that occur during tissue remodeling (By similarity). D-fructose 6-phosphate + L-glutamine = D-glucosamine 6-phosphate + L-glutamate Nucleotide-sugar biosynthesis; UDP-N-acetyl-alpha-D-glucosamine biosynthesis; alpha-D-glucosamine 6-phosphate from D-fructose 6-phosphate: step 1/1. Homotetramer, may also exist as homodimers. Isoform 1 is predominantly expressed in hindlimb muscle and is also expressed weakly in the heart. Seems to be selectively expressed in striated muscle. Expression in the liver oscillates in an ultradian manner (with a 12 hour period/cycle).