Species: Escherichia coli K-12 substr. MG1655
Subunit composition of glutaminase B = [glutaminase B monomer]4
Two glutaminases were purified from E. coli B. They differ in their pH optima and regulation [Prusiner71]. Glutaminase B is active at neutral and alkaline pH [Prusiner76a], and the enzyme is constitutive [Prusiner75].
Molecular Weight of Polypeptide: 22.5 kD (from nucleotide sequence)
Molecular Weight of Multimer: 90.0 kD (experimental) [Prusiner76a]
pI: 5.4 [Prusiner76a]
Enzymatic reaction of: glutaminase B
Synonyms: glutaminase, L-glutamine amidohydrolase
EC Number: 18.104.22.168L-glutamine + H2O → L-glutamate + ammonium
The direction shown, i.e. which substrates are on the left and right sides, is in accordance with the direction in which it was curated.
The reaction is physiologically favored in the direction shown.
Alternative Substrates [ Comment 1]:
In Pathways: L-glutamine degradation IL-glutamate [Prusiner76b, Prusiner76] Activators (Unknown Mechanism): borate [Prusiner76b], Mg2+ [Prusiner76], Mn2+ [Prusiner76], Ca2+ [Prusiner76], AMP [Prusiner76], diphosphate [Prusiner76], PPPi [Prusiner76] Inhibitors (Competitive): L-glutamate [Prusiner76b, Comment 2] Inhibitors (Unknown Mechanism): borate [Prusiner76b], ATP [Prusiner76], ADP [Prusiner76], adenosine tetraphosphate [Prusiner76], NAD+ [Prusiner76], NADH [Prusiner76], NADP+ [Prusiner76], NADPH [Prusiner76]
pH(opt): 7.1-9 [Prusiner76a]
Prusiner76b: Prusiner S, Stadtman ER (1976). "Regulation of glutaminase B in Escherichia coli. II. Modulaltion of activity by carbosylate and borate ions." J Biol Chem 1976;251(11);3457-62. PMID: 776969
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