Glucosamine-6-phosphate synthase [isomerizing] (GlmS)

Glucosamine-6-phosphate synthase (GlmS) is a vital enzyme in the hexosamine biosynthetic pathway, catalyzing the first committed and rate-limiting step: the conversion of L-glutamine and D-fructose-6-phosphate into D-glucosamine-6-phosphate and L-glutamate. In bacteria, the product glucosamine-6-phosphate is an essential precursor for the synthesis of peptidoglycan and lipopolysaccharides, which are critical components of the bacterial cell wall and outer membrane. Because the enzyme is indispensable for bacterial survival and growth, it is a prominent target for the development of novel antibacterial agents, especially against multidrug-resistant strains like Staphylococcus aureus. While a human homolog (GFAT) exists, structural differences—such as the dimeric nature of the bacterial enzyme compared to the tetrameric human version—provide a basis for selective inhibition. Drugs and experimental inhibitors, such as the natural pro-drug bacilysin and synthetic analogues like FMDP, target the enzyme's active site to disrupt cell wall integrity, ultimately leading to bacterial cell lysis.

Other names

L-glutamine:D-fructose-6-phosphate amidotransferaseGlcN-6-P synthaseGlucosamine-6-phosphate isomerase (glutamine-forming)Hexosamine-6-phosphate synthaseGlutamine-fructose-6-phosphate aminotransferase [isomerizing]

Inhibition of the enzyme prevents the formation of glucosamine-6-phosphate, thereby depleting the pool of precursors required for peptidoglycan synthesis, which leads to impaired cell wall assembly and bacterial death.