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Literature summary for 6.3.1.2 extracted from

  • Alibhai, M.; Villafranca, J.J.
    Kinetic and mutagenic studies of the role of the active site residues Asp-50 and Glu-327 of Escherichia coli glutamine synthetase (1994), Biochemistry, 33, 682-686.
    View publication on PubMed

Protein Variants

Protein Variants Comment Organism
D50E mutant D50E shows activity with Mn2+ but very low activity with Mg2+, and altered kcat/Km values for all three substrates. Mutant E327A has a decreased kcat/Km value for NH4+ compared to that of the wild-type enzyme. Asp-50 is likely involved in binding NH4+ and may also play a role in catalyzing deprotonation of NH4+ to form NH3. Glu-327 participates in lowering the free energy of the transition state involved in formation of the positively charged tetrahedral adduct resulting from the condensation of gamma-glutamyl phosphate and NH3 Escherichia coli

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
additional information
-
additional information Km-values of wild-type and mutant enzymes D50A, D50E, E327A Escherichia coli
4.9
-
Gln
-
Escherichia coli

Organism

Organism UniProt Comment Textmining
Escherichia coli
-
wild-type and site-directed mutants
-
Escherichia coli
-
wild-type and site-directed mutants H4A, H4C, M8L, H12L, H12D
-

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
ATP + L-Glu + NH4+
-
Escherichia coli ADP + phosphate + L-Gln
-
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