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Literature summary for 2.6.1.16 extracted from

  • Wei, W.; Monard, G.; Gauld, J.
    Computational insights into substrate binding and catalytic mechanism of the glutaminase domain of glucosamine-6-phosphate synthase (GlmS) (2017), RSC Adv., 7, 29626-29638 .
No PubMed abstract available
Search for more literature for 2.6.1.16

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
additional information
-
 additional information thermodynamics Escherichia coli

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
L-glutamine + D-fructose 6-phosphate Escherichia coli
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 L-glutamate + D-glucosamine 6-phosphate
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 ?

Organism

Organism UniProt Comment Textmining
Escherichia coli P17169
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Reaction

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
a

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
L-glutamine + D-fructose 6-phosphate
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 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 ?
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-

Synonyms

Synonyms Comment Organism
GlmS
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 Escherichia coli
glucosamine-6-phosphate synthase
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 Escherichia coli

General Information

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