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106  structures 2786  species 1  interaction 4121  sequences 56  architectures

Family: Glutaminase (PF04960)

Summary: Glutaminase

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This is the Wikipedia entry entitled "Glutaminase". More...

Glutaminase Edit Wikipedia article

EC number3.5.1.2
CAS number9001-47-2
IntEnzIntEnz view
ExPASyNiceZyme view
MetaCycmetabolic pathway
PDB structuresRCSB PDB PDBe PDBsum
Gene OntologyAmiGO / QuickGO
PDB 2osu EBI.jpg
probable glutaminase from bacillus subtilis complexed with 6-diazo-5-oxo-l-norleucine
Pfam clanCL0013

Glutaminase (EC, glutaminase I, L-glutaminase, glutamine aminohydrolase) is an amidohydrolase enzyme that generates glutamate from glutamine. Glutaminase has tissue-specific isoenzymes. Glutaminase has an important role in glial cells.

Glutaminase catalyzes the following reaction:

Glutamine + H2O → glutamate + NH3

Tissue distribution

Glutaminase is expressed and active in periportal hepatocytes, where it generates NH3 (ammonia) for urea synthesis, as does glutamate dehydrogenase.[2] 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 chronic 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 0.26 mM (compared to an arterial blood ammonia of 0.02 mM).

One of the most important roles of glutaminase is found in the axonal terminals of neurons in the central nervous system. Glutamate is the most abundantly used excitatory neurotransmitter in the CNS. After being released into the synapse for neurotransmission, glutamate is rapidly taken up by nearby astrocytes, which convert it to glutamine. This glutamine is then supplied to the presynaptic terminals of the neurons, where glutaminases convert it back to glutamate for loading into synaptic vesicles. Although both "kidney-type" (GLS1) and "liver-type" (GLS2) glutaminases are expressed in brain, GLS2 has been reported to exist only in cellular nuclei in CNS neurons.[3]


ADP is the strongest adenine nucleotide activator of glutaminase. Studies have also suggested ADP lowered the Km for glutamine and increased the Vmax. They found that these effects were increased even more when ATP was present.[4]

Phosphate-activated mitochondrial glutaminase (GLS1) is suggested to be linked with elevated metabolism, decreased intracellular reactive oxygen species (ROS) levels, and overall decreased DNA oxidation in both normal and stressed cells. It is suggested that GLS1’s control of ROS levels facilitates “the ability of p53 to protect cells from accumulation of genomic damage and allows cells to survive after mild and repairable genotoxic stress.”[5]


The structure of glutaminase has been determined using X-ray diffraction to a resolution of up to 1.73 Ã…. There are 2 chains containing 305 residues that make up the length of this dimeric protein. On each strand, 23% of the amino acid content, or 71 residues, are found in the 8 helices. Twenty-one percent, or 95 residues, make up the 23 beta sheet strands.[1]


Humans express 4 isoforms of glutaminase. GLS encodes 2 types of kidney-type glutaminase with a high activity and low Km. GLS2 encodes 2 forms of liver-type glutaminase with a low activity and allosteric regulation.[2]

NCBI gene2744
Other data
EC number3.5.1.2
LocusChr. 2 q32-q34
glutaminase 2
(liver, mitochondrial)
NCBI gene27165
Other data
EC number3.5.1.2
LocusChr. 12 q13

Related proteins

Glutaminases belong to a larger family that includes serine-dependent beta-lactamases and penicillin-binding proteins. Many bacteria have two isozymes. This model is based on selected known glutaminases and their homologs within prokaryotes, with the exclusion of highly derived (long-branch) and architecturally varied homologs, so as to achieve conservative assignments. A sharp drop in scores occurs below 250, and cutoffs are set accordingly. The enzyme converts glutamine to glutamate, with the release of ammonia. Members tend to be described as glutaminase A (glsA), where B (glsB) is unknown and may not be homologous (as in Rhizobium etli; some species have two isozymes that may both be designated A (GlsA1 and GlsA2).

Clinical significance

Many cancers rely on glutaminase thus glutaminase inhibitors have been proposed as a cancer treatment.[6][7] As of July 2018 some glutaminase inhibitors are in mid-stage clinical trials.


  1. ^ a b PDB: 3A56​; Hashizume R, Mizutani K, Takahashi N, Matsubara H, Matsunaga A, Yamaguchi S, Mikami B (2010). "Crystal structure of protein-glutaminase". doi:10.2210/pdb3a56/pdb. Cite journal requires |journal= (help)
  2. ^ a b Van Noorden, Botman (August 2014). "Determination of Phosphate-activated Glutaminase Activity and Its Kinetics in Mouse Tissues using Metabolic Mapping (Quantitative Enzyme Histochemistry)" (PDF). Journal of Histochemistry & Cytochemistry. 62 (11): 813–26. doi:10.1369/0022155414551177. PMC 4230542. PMID 25163927. Retrieved 26 September 2014.
  3. ^ Olalla L, Gutiérrez A, Campos JA, Khan ZU, Alonso FJ, Segura JA, Márquez J, Aledo JC (Aug 2002). "Nuclear localization of L-type glutaminase in mammalian brain". J. Biol. Chem. 277 (41): 38939–38944. doi:10.1074/jbc.C200373200. PMID 12163477.
  4. ^ Masola B, Ngubane NP (December 2010). "The activity of phosphate-dependent glutaminase from the rat small intestine is modulated by ADP and is dependent on integrity of mitochondria". Arch. Biochem. Biophys. 504 (2): 197–203. doi:10.1016/ PMID 20831857.
  5. ^ Suzuki S, Tanaka T, Poyurovsky MV, Nagano H, Mayama T, Ohkubo S, Lokshin M, Hosokawa H, Nakayama T, Suzuki Y, Sugano S, Sato E, Nagao T, Yokote K, Tatsuno I, Prives C (April 2010). "Phosphate-activated glutaminase (GLS1), a p53-inducible regulator of glutamine metabolism and reactive oxygen species". Proc. Natl. Acad. Sci. U.S.A. 107 (16): 7461–6. doi:10.1073/pnas.1002459107. PMC 2867754. PMID 20351271.
  6. ^ Chen, L; Cui, H (2015). "Targeting Glutamine Induces Apoptosis: A Cancer Therapy Approach". International Journal of Molecular Sciences. 16 (9): 22830–55. doi:10.3390/ijms160922830. PMC 4613338. PMID 26402672.
  7. ^ Sheikh, T. N; Patwardhan, P. P; Cremers, S; Schwartz, G. K (2017). "Targeted inhibition of glutaminase as a potential new approach for the treatment of NF1 associated soft tissue malignancies". Oncotarget. 8 (55): 94054–94068. doi:10.18632/oncotarget.21573. PMC 5706855. PMID 29212209.

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This page is based on a Wikipedia article. The text is available under the Creative Commons Attribution/Share-Alike License.

This tab holds the annotation information that is stored in the Pfam database. As we move to using Wikipedia as our main source of annotation, the contents of this tab will be gradually replaced by the Wikipedia tab.

Glutaminase Provide feedback

This family of enzymes deaminates glutamine to glutamate EC:

External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR015868

Glutaminases (EC) deaminate glutamine to glutamate. In Bacillus subtilis, glutaminase is encoded by glnA, which is part of an operon, glnA-glnT (formerly ybgJ-ybgH), where glnT encodes a glutamine transporter. The glnA-glnT operon is regulated by the 2-component system GlnK-GlnL in response to glutamine [PUBMED:15995196]. This entry represents the core structural motif of a family of glutaminases that include GlnA, which are characterised by their beta-lactamase-like topology, containing a cluster of alpha-helices and an alpha/beta sandwich.

This family describes the enzyme glutaminase, from a larger family that includes serine-dependent beta-lactamases and penicillin-binding proteins. Many bacteria have two isozymes. This model is based on selected known glutaminases and their homologues within prokaryotes, with the exclusion of highly-derived (long branch) and architecturally varied homologues, so as to achieve conservative assignments. A sharp drop in scores occurs below 250, and cutoffs are set accordingly. The enzyme converts glutamine to glutamate, with the release of ammonia. Members tend to be described as glutaminase A (glsA), where B (glsB) is unknown and may not be homologous (as in Rhizobium etli. Some species have two isozymes that may both be designated A (GlsA1 and GlsA2).

Gene Ontology

The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.

Domain organisation

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Pfam Clan

This family is a member of clan Beta-lactamase (CL0013), which has the following description:

This superfamily contains proteins that have a beta-lactamase fold. This includes beta-lactamases as well as Dala-Dala carboxypeptidases and glutaminases.

The clan contains the following 6 members:

Beta-lactamase Beta-lactamase2 Glutaminase Peptidase_S11 Peptidase_S13 Transpeptidase


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Curation and family details

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Seed source: COG2066
Previous IDs: none
Type: Domain
Sequence Ontology: SO:0000417
Author: Bateman A
Number in seed: 287
Number in full: 4121
Average length of the domain: 268.40 aa
Average identity of full alignment: 40 %
Average coverage of the sequence by the domain: 68.93 %

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HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 47079205 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 21.0 21.0
Trusted cut-off 21.0 21.0
Noise cut-off 20.5 20.9
Model length: 286
Family (HMM) version: 16
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Species distribution

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Archea Archea Eukaryota Eukaryota
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For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the PDBe group, to allow us to map Pfam domains onto UniProt sequences and three-dimensional protein structures. The table below shows the structures on which the Glutaminase domain has been found. There are 106 instances of this domain found in the PDB. Note that there may be multiple copies of the domain in a single PDB structure, since many structures contain multiple copies of the same protein sequence.

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