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Literature summary for 3.5.1.2 extracted from

  • Roberg, B.A.; Torgner, I.A.; Kvamme, E.
    Kinetics of a novel isoform of phosphate activated glutaminase (PAG) in SH-SY5Y neuroblastoma cells (2010), Neurochem. Res., 35, 875-880.
    View publication on PubMed
Search for more literature for 3.5.1.2

Activating Compound

Activating Compound Comment Organism Structure
phosphate homogenate protein of SH-SY5Y cells: without phosphate about 12% L-glutamine hydrolysis at 150 mM 119 nmol/min, at 0 mM 14 nmol/min, soluble and membrane-associated enzyme forms are phosphate-activated, but without phosphate about 25% activity remains compared to the addition of 150 mM phosphate. In the brain protein fraction no L-glutamine hydrolysis is found without phosphate. N-PAG in whole cell homogenates in mitochondrial buffer is activated by high concentrations of phosphate, showing hyperbolic kinetics with a Ka of ca. 41 mM Homo sapiens

Inhibitors

Inhibitors Comment Organism Structure
L-glutamine product inhibition, strongly inhibits the membrane-associated enzyme, while the soluble form is not or weakly inhibited Homo sapiens
NH3 product inhibition, 10 mM inhibits the enzyme activity about 30% Homo sapiens

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
3
-
 L-glutamine lower than, soluble and membrane-associated N-PAG, 37°C, pH 8.6 Homo sapiens
4
-
 L-glutamine brain, membrane-associated PAG, 37°C, pH 8.6 Homo sapiens
26
-
 L-glutamine brain, soluble PAG, 37°C, pH 8.6 Homo sapiens

Localization

Localization Comment Organism GeneOntology No. Textmining
membrane membrane associated Homo sapiens 16020
-
mitochondrion neuroblastomal PAG is mitochondrial, enriched in mitochondria by 606% compared to the cell homogenate Homo sapiens 5739
-
soluble
-
 Homo sapiens
-
-

Molecular Weight [Da]

Molecular Weight [Da] Molecular Weight Maximum [Da] Comment Organism
58000
-
 N-PAG, immunoblot analysis, C-terminal antibody reacts with the protein of 65000 Da, while the N-terminal antibody primarily labels a protein of 58000 Da and to a minor degree one of 65000 Da. This strongly suggests that neuroblastoma cells mainly contain an active isoform of PAG lacking the C-terminal end, probably the GAC form, a splicing variant Homo sapiens
65000
-
 N-PAG, immunoblot analysis, C-terminal antibody reacts with the protein of 65000 Da, while the N-terminal antibody primarily labels a protein of 58000 Da and to a minor degree one of 65000 Da. This strongly suggests that neuroblastoma cells mainly contain an active isoform of PAG lacking the C-terminal end, probably the GAC form, a splicing variant Homo sapiens

Organism

Organism UniProt Comment Textmining
Homo sapiens
-
-
-

Source Tissue

Source Tissue Comment Organism Textmining
brain
-
 Homo sapiens
-
SH-SY5Y cell neuroblastoma cells, N-PAG, the proliferation state of the cells influence the specific activity. It is maximal at the start of the exponential phase of growth and is gradually reduced to a lower but significant level when the cell culture ceases to divide Homo sapiens
-

Specific Activity [micromol/min/mg]

Specific Activity Minimum [µmol/min/mg] Specific Activity Maximum [µmol/min/mg] Comment Organism
additional information
-
 the proliferation state of the cells influence the specific activity. It is maximal at the start of the exponential phase of growth and is gradually reduced to a lower but significant level when the cell culture ceases to divide Homo sapiens

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
L-glutamine + H2O
-
 Homo sapiens L-glutamate + NH3
-
 ?

Synonyms

Synonyms Comment Organism
mitochondrial glutaminase
-
 Homo sapiens
N-PAG
-
 Homo sapiens
neuroblastoma glutaminase
-
 Homo sapiens
neuroblastoma PAG
-
 Homo sapiens
phosphate-activated glutaminase
-
 Homo sapiens

Temperature Optimum [°C]

Temperature Optimum [°C] Temperature Optimum Maximum [°C] Comment Organism
37
-
 assay at Homo sapiens

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
8.6
-
 assay at Homo sapiens