l-Glutamine
d-Fructose-6-P aminotransferase regulates hexosamine synthesis. An affinity purified human fibroblast aminotransferase and specific radioisotope assays developed by us were used to show an independent inhibition of the aminotransferase by Glucose-6-P. More interestingly, at concentration of UDP-N-Acetylglucosamine and glucose-6-P where either sugar has no independent inhibitory effect, there is an allosteric and significant inhibition of the aminotransferase.