Inhibition of glucosamine-6-phosphate synthetase from bacteria by anticapsin

On the basis of kinetic studies on glucosamine-6-phosphate synthetase (EC 5.3.1.19) from six bacteria sources it has been shown that the epoxyamino acid anticapsin, a glutamine analog, is a competitive inhibitor of the enzyme in regard to glutamine with Km value of 10(-4) M and Ki varying from 10(-7) to 10(-6) M. Unlike other glutamine analogs like 6-diazo-5-oxo-L-norleucine, chloropentanoic acid, L-alpha-amino-3-chloro-4,5-dihydro-5-isoxazole acetic acid or albizziin, anticapsin is not generally inhibitory to various amidotransferases. It does not inhibit xanthosine 5'-monophosphate amidotransferase, glutaminase or gamma-glutamyltranspeptidase.