Glutaminase

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glutaminase
Identifiers
Symbol GLS
Entrez 2744
HUGO 4331
OMIM 138280
RefSeq NM_014905
UniProt O94925
Other data
EC number 3.5.1.2
Locus Chr. 2 q32-q34
glutaminase 2 (liver, mitochondrial)
Identifiers
Symbol GLS2
Entrez 27165
HUGO 29570
OMIM 606365
RefSeq NM_013267
UniProt Q9UI32
Other data
Locus Chr. 12 q13

Glutaminase is an amidohydrolase enzyme which generates glutamate from glutamine. Glutaminase has tissue-specific isoenzymes.

Glutaminase catalyzes the following reaction:

Glutamine + H2O → Glutamate + NH3

Glutaminase is expressed in periportal hepatocytes, where it generates NH3 (ammonia) for urea synthesis, as does glutamate dehydrogenase.

Glutaminase is also expressed in the epithelial cells of the renal tubules, where the produced ammonia is excreted as ammonium ions. This excretion of ammonium ions is an important mechanism of renal acid-base regulation. During an acidosis, glutaminase is induced in the kidney, which leads to an increase in the amount of ammonium ions excreted.

Glutaminase can also be found in the intestines, whereby hepatic portal ammonia can reach as high as 0.26mM (compared to an arterial blood ammonia of 0.02mM).

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v • d • e
Carbon-nitrogen non-peptide hydrolases (EC 3.5)
3.5.1 - Amidohydrolases
3.5.2
3.5.3
3.5.4 - Aminohydrolases
Other
v • d • e
Metabolism: amino acid metabolism - synthesis and catabolism enzymes (essential in CAPS)
K→acetyl-CoA
(see below)
G→pyruvate
G→glutamate
G→propionyl-CoA
→succinyl-CoA→TCA
G→fumarate
G→oxaloacetate
Other
Glutamine synthetase - Glutaminase
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