EC 1 - Oxidoreductases
EC 1.4 - Acting on the CH-NH2 group of donors
EC 1.4.1 - With NAD+ or NADP+ as acceptor
EC 1.4.1.13 - Glutamate synthase (NADPH)
IntEnz Enzyme Nomenclature
EC 1.4.1.13
Names
L-glutamate synthetase
L-glutamine:2-oxoglutarate aminotransferase, NADPH oxidizing
NADPH-dependent glutamate synthase
NADPH-glutamate synthase
NADPH-linked glutamate synthase
glutamate (reduced nicotinamide adenine dinucleotide phosphate) synthase
glutamate synthetase (NADP)
glutamine amide-2-oxoglutarate aminotransferase (oxidoreductase, NADP)
glutamine-ketoglutaric aminotransferase
GOGAT
Reactions
- (1) 2 L-glutamate + NADP+ = L-glutamine + 2-oxoglutarate + NADPH + H+
- (1a) L-glutamate + NH3 = L-glutamine + H2O
- (1b) L-glutamate + NADP+ + H2O = NH3 + 2-oxoglutarate + NADPH + H+
Cofactors
Comments:
Binds FMN, FAD, 2 [4Fe-4S] clusters and 1 [3Fe-4S] cluster. The reaction takes place in the opposite direction. The protein is composed of two subunits, α and β. The α subunit is composed of two domains, one hydrolysing L-glutamine to NH3 and L-glutamate (cf. EC 3.5.1.2, glutaminase), the other combining the produced NH3 with 2-oxoglutarate to produce a second molecule of L-glutamate (cf. EC 1.4.1.4, glutamate dehydrogenase [NADP+]). The β subunit transfers electrons from the cosubstrate. The NH3 is channeled through a 31 Å channel in the active protein. In the absence of the β subunit, coupling between the two domains of the α subunit is compromised and some ammonium can be produced. In the intact αβ complex, ammonia production only takes place as part of the overall reaction.
Links to other databases
References
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Glutamate synthase from Escherichia coli. An iron-sulfide flavoprotein.J. Biol. Chem. 247 : 7407-7419 (1972). [PMID: 4565085]
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Synthesis of glutamate in Aerobacter aerogenes by a hitherto unknown route.Biochem. J. 117 : 405-407 (1970). [PMID: 5420057]
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Glutamate synthase: a complex iron-sulfur flavoprotein.Cell. Mol. Life Sci. 55 : 617-638 (1999). [PMID: 10357231]
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Determination of the midpoint potential of the FAD and FMN flavin cofactors and of the 3Fe-4S cluster of glutamate synthase.Biochemistry 40 : 5533-5541 (2001). [PMID: 11331018]
[EC 1.4.1.13 created 1972 as EC 2.6.1.53, transferred 1976 to EC 1.4.1.13, modified 2001, modified 2010]