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. 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. Highest levels of expression in heart, placenta, and spinal cord.