Literature summary for 6.3.1.2 extracted from

Yin, Z.; Purschke, W.G.; Schafer, G.; Schmidt, C.L.
The glutamine synthetase from the hyperthermoacidophilic crenarcheon Sulfolobus acidocaldarius: isolation, characterization and sequencing of the gene (1998), Biol. Chem., 379, 1349-1354.

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General Stability

General Stability	Organism
Mn2+ or Mg2+ required for stability, Mn2+ more effective than Mg2+	Sulfolobus acidocaldarius

Inhibitors

Inhibitors	Comment	Organism	Structure
AMP	slight inhibition of the biosynthetic reaction	Sulfolobus acidocaldarius
glycine	feed-back inhibition, competitive with L-glutamine	Sulfolobus acidocaldarius
L-alanine	feed-back inhibition, competitive with L-glutamine	Sulfolobus acidocaldarius
additional information	no effect with L-histidine or L-tryptophane	Sulfolobus acidocaldarius

KM Value [mM]

KM Value [mM]	KM Value Maximum [mM]	Substrate	Comment	Organism	Structure
0.15	-	ADP	80°C	Sulfolobus acidocaldarius
0.24	-	Mn2+	80°C	Sulfolobus acidocaldarius
1.3	-	L-glutamine	80°C	Sulfolobus acidocaldarius

Localization

Localization	Comment	Organism	GeneOntology No.	Textmining
cytosol	-	Sulfolobus acidocaldarius	5829	-

Metals/Ions

Metals/Ions	Comment	Organism	Structure
Mg2+	required for activity and for stability	Sulfolobus acidocaldarius
Mn2+	required for activity and for stability	Sulfolobus acidocaldarius

Molecular Weight [Da]

Molecular Weight [Da]	Molecular Weight Maximum [Da]	Comment	Organism
50000	55000	SDS-PAGE	Sulfolobus acidocaldarius
52000	-	calculated from amino acid sequence	Sulfolobus acidocaldarius
630000	-	gel filtration	Sulfolobus acidocaldarius

Natural Substrates/ Products (Substrates)

Natural Substrates	Organism	Comment (Nat. Sub.)	Natural Products	Comment (Nat. Pro.)	Rev.	Reac.
ATP + glutamate + NH4+	Sulfolobus acidocaldarius	central enzyme of nitrogen metabolism	ADP + phosphate + L-glutamine	-	r

Organism

Organism	UniProt	Comment	Textmining
Sulfolobus acidocaldarius	Q9HH09	strain DSM 639, hypothermoacidophilic crenarcheon	-

Purification (Commentary)

Purification (Comment)	Organism
-	Sulfolobus acidocaldarius

Specific Activity [micromol/min/mg]

Specific Activity Minimum [µmol/min/mg]	Specific Activity Maximum [µmol/min/mg]	Comment	Organism
26.8	-	80°C, purified enzyme	Sulfolobus acidocaldarius

Substrates and Products (Substrate)

Substrates	Comment Substrates	Organism	Products	Comment (Products)	Rev.	Reac.
ATP + glutamate + NH4+	-	Sulfolobus acidocaldarius	ADP + phosphate + L-glutamine	-	r
ATP + glutamate + NH4+	central enzyme of nitrogen metabolism	Sulfolobus acidocaldarius	ADP + phosphate + L-glutamine	-	r

Subunits

Subunits	Comment	Organism
dodecamer	12 * 52000, native mass by gel filtration, subunit mass calculated from amino acid sequence	Sulfolobus acidocaldarius

Temperature Optimum [°C]

Temperature Optimum [°C]	Temperature Optimum Maximum [°C]	Comment	Organism
90	-	-	Sulfolobus acidocaldarius

Temperature Stability [°C]

Temperature Stability Minimum [°C]	Temperature Stability Maximum [°C]	Comment	Organism
78	-	stable for at least 100 min in the presence of 4 mM Mn2+, 50% loss of activity in the absence of Mn2+ or Mg2+ within 100 min	Sulfolobus acidocaldarius

pH Optimum

pH Optimum Minimum	pH Optimum Maximum	Comment	Organism
7	7.5	-	Sulfolobus acidocaldarius

Ki Value [mM]

Ki Value [mM]	Ki Value maximum [mM]	Inhibitor	Comment	Organism	Structure
0.03	-	L-alanine	80°C	Sulfolobus acidocaldarius
0.1	-	glycine	80°C	Sulfolobus acidocaldarius

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Release 2023.1 (January 2023)