KM Value [mM] | KM Value Maximum [mM] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
additional information | - |
additional information | thermodynamics | Escherichia coli |
Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
L-glutamine + D-fructose 6-phosphate | Escherichia coli | - |
L-glutamate + D-glucosamine 6-phosphate | - |
? |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Escherichia coli | P17169 | - |
- |
Reaction | Comment | Organism | Reaction ID |
---|---|---|---|
L-glutamine + D-fructose 6-phosphate = L-glutamate + D-glucosamine 6-phosphate | analysis of two catalytic mechanism variants (with neutral Cys1NH2 as the activating base or with His71 as the activating base) by molecular dynamics (MD) and quantum mechanics/molecular mechanics (QM/MM) computational methods, detailed overview. Results shows that the most likely catalytic mechanism is determined to involve a neutral Cys1NH2 group acting as the base that activates the Cys1 thiol | Escherichia coli |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
L-glutamine + D-fructose 6-phosphate | - |
Escherichia coli | L-glutamate + D-glucosamine 6-phosphate | - |
? | |
additional information | the glutaminase domain catalyzes the conversion of glutamine to glutamic acid with the release of ammonia | Escherichia coli | ? | - |
- |
Synonyms | Comment | Organism |
---|---|---|
GlmS | - |
Escherichia coli |
glucosamine-6-phosphate synthase | - |
Escherichia coli |
General Information | Comment | Organism |
---|---|---|
additional information | the glutaminase domain catalyzes the conversion of glutamine to glutamic acid with the release of ammonia. A catalytically important cysteinyl (Cys1) has been suggested to act as the mechanistic nucleophile after being activated by the N-terminal amine of the glutaminase domain (i.e. its own alpha-amine). Using molecular dynamics (MD) and quantum mechanics/molecular mechanics (QM/MM) computational methods, the active site of the glutaminase domain, the protonation state of its N-terminal amine, substrate binding, and catalytic mechanism are analysed, potential for an active site histidyl (His71) to alternatively act as the required base. A tetrahedral oxyanion intermediate is formed during the mechanism, stabilized by a water and two enzyme residues: Asn98 and Gly99. The overall rate-limiting step of the mechanism is the nucleophilic attack of a water on the thioester cross-linked intermediate with a barrier of 74.4 kJ/mol. An alternate mechanism in which His71 acts as the nucleophile-activating base, and which requires the Cys1 alpha-amine to be protonated, is calculated to be enzymatically feasible but to have a much higher overall rate-limiting barrier of 93.7 kJ/mol. Structure-function analysis and enzyme-substrate binding, overview | Escherichia coli |
physiological function | glucosamine-6-phosphate synthase (GlmS) is a key enzyme in the biosynthesis of hexosamine | Escherichia coli |