Involved in the first step in the biosynthesis of amino-sugar-nucleotides. Catalyzes the hydrolysis of the N-acetyl group of N-acetylglucosamine-6-phosphate (GlcNAc-6-P) to yield glucosamine 6-phosphate and acetate. In vitro, can also hydrolyze substrate analogs such as N-thioacetyl-D-glucosamine-6-phosphate, N-trifluoroacetyl-D-glucosamine-6-phosphate, N-acetyl-D-glucosamine-6-sulfate, N-acetyl-D-galactosamine-6-phosphate, and N-formyl-D-glucosamine-6-phosphate. H2O + N-acetyl-D-glucosamine 6-phosphate = acetate + D-glucosamine 6-phosphate Binds 1 divalent metal cation per subunit. The highest efficient metals are Zn(2+) and Co(2+), followed by Mn(2+), Cd(2+), Fe(2+) and Ni(2+). Inhibited by high substrate concentration and by products glucosamine 6-phosphate and acetate. Completely inactivated by the treatment with 5,5'-dithio-bis(2-nitrobenzoate) or 2,2'-dithio-pyridine (2-DPDS). Inhibited by 1,10-phenanthroline and EDTA. kcat is 102 sec(-1) for the deacetylation of N-acetyl-D-glucosamine-6-phosphate by the Zn-enzyme. The Cd-NagA catalyzes the hydrolysis of N-thioacetyl-D-glucosamine-6-phosphate substrate about an order of magnitude better than does the Zn-substituted enzyme. The N-trifluoroacetyl substituted substrate is hydrolyzed 26 times faster than the natural substrate, but the N-formyl substrate is hydrolyzed more slowly by a factor of 5. Optimum pH is 8.5. Amino-sugar metabolism; N-acetylneuraminate degradation; D-fructose 6-phosphate from N-acetylneuraminate: step 4/5. Homotetramer. By N-acetylglucosamine. Induced by low extracellular levels of magnesium via the PhoQ/PhoP two-component regulatory system. Synthesizes high levels of glucosamine-6-phosphate deaminase and over half of the amount of glucosamine-6-phosphate synthase compared to wild-type. Belongs to the metallo-dependent hydrolases superfamily. NagA family.