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Literature summary for 6.3.1.2 extracted from

  • Healy, F.G.; Latorre, C.; Albrecht, S.L.; Reddy, P.M.; Shanmugam, K.T.
    Altered kinetic properties of tyrosine-183 to cysteine mutation in glutamine synthetase of Anabaena variabilis strain SA1 is responsible for excretion of ammonium ion produced by nitrogenase (2003), Curr. Microbiol., 46, 423-431.
    View publication on PubMed

Cloned(Commentary)

Cloned (Comment) Organism
SA0 and SA1 expressed in Escherichia coli SE3000 Trichormus variabilis

Inhibitors

Inhibitors Comment Organism Structure
alanine more inhibitory for enzyme from strain SA0 than for enzyme from SA1 Trichormus variabilis
aspartate more inhibitory for enzyme from strain SA0 than for enzyme from SA1 Trichormus variabilis
cysteine more inhibitory for enzyme from strain SA0 than for enzyme from SA1 Trichormus variabilis
glycine more inhibitory for enzyme from strain SA0 than for enzyme from SA1 Trichormus variabilis
L-methionine sulfone inhibits enzyme from strain SA0 but not from SA1, more than 80% inhibition at 0.05 mM Trichormus variabilis
L-methionine-DL-sulfoximine inhibits enzyme from strain SA0 but not from SA1, more than 80% inhibition at 0.05 mM Trichormus variabilis
Mn2+ inhibitory for enzyme from strain SA0 Trichormus variabilis
serine more inhibitory for enzyme from strain SA0 than for enzyme from SA1 Trichormus variabilis

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
0.004
-
NH4+ enzyme from strain SA0, pH 6.8 Trichormus variabilis
0.015
-
NH4+ enzyme from strain SA0, pH 7.5 Trichormus variabilis
0.1
-
ATP enzyme from strain SA0, pH 6.8 Trichormus variabilis
0.13
-
ATP enzyme from strain SA0, pH 7.5 Trichormus variabilis
0.17
-
ATP enzyme from strain SA1, pH 6.8 Trichormus variabilis
0.21
-
ATP enzyme from strain SA1, pH 7.5 Trichormus variabilis
1.4
-
glutamate enzyme from strain SA0, pH 6.8 Trichormus variabilis
1.4
-
NH4+ enzyme from strain SA1, pH 7.5 Trichormus variabilis
1.7
-
glutamate enzyme from strain SA0, pH 7.5 Trichormus variabilis
9.2
-
glutamate enzyme from strain SA1, pH 6.8 Trichormus variabilis
12.4
-
NH4+ enzyme from strain SA1, pH 6.8 Trichormus variabilis
16.8
-
glutamate enzyme from strain SA1, pH 7.5 Trichormus variabilis

Metals/Ions

Metals/Ions Comment Organism Structure
Mg2+ required for optimum activity of enzyme from strain SA0, no activation of enzyme from strain SA1 Trichormus variabilis
Mn2+ required for optimum activity of enzyme from strain SA1, highest activity at 0.3 mM, concentration inhibitory for enzyme from SA0 Trichormus variabilis

Molecular Weight [Da]

Molecular Weight [Da] Molecular Weight Maximum [Da] Comment Organism
52000
-
SDS-PAGE Trichormus variabilis
53080
-
calculated from amino acid sequence Trichormus variabilis
625000
-
gel filtration Trichormus variabilis

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
ATP + glutamate + NH4+ Trichormus variabilis central enzyme of nitrogen metabolism, provides glutamine for biosynthesis, ammonia assimilation ADP + phosphate + L-glutamine
-
?

Organism

Organism UniProt Comment Textmining
Trichormus variabilis
-
strains SA0 and SA1, SA1 carries a single amino acid mutation Y183C and is defective in ammonia assimilation below concentrations of 0.5 mM
-

Purification (Commentary)

Purification (Comment) Organism
from both strains Trichormus variabilis

Specific Activity [micromol/min/mg]

Specific Activity Minimum [µmol/min/mg] Specific Activity Maximum [µmol/min/mg] Comment Organism
12.1
-
purified enzyme from strain SA1 Trichormus variabilis
126.1
-
purified enzyme from strain SA0 Trichormus variabilis

Storage Stability

Storage Stability Organism
-70°C, concentrated solution in 50% glycerol, 2 months, 4% loss of activity Trichormus variabilis

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
ATP + glutamate + NH4+
-
Trichormus variabilis ADP + phosphate + L-glutamine
-
?
ATP + glutamate + NH4+ central enzyme of nitrogen metabolism, provides glutamine for biosynthesis, ammonia assimilation Trichormus variabilis ADP + phosphate + L-glutamine
-
?

Subunits

Subunits Comment Organism
dodecamer 12 * 52000, subunit mass by SDS-PAGE, native mass by gel filtration Trichormus variabilis

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
6.8
-
strain SA1 Trichormus variabilis
7.5
-
strain SA0 Trichormus variabilis