Glutamate synthase (NADPH) explained

glutamate synthase (NADPH)
Ec Number:	1.4.1.13
Cas Number:	37213-53-9
Go Code:	0004355
Width:	270

In enzymology, a glutamate synthase (NADPH) is an enzyme that catalyzes the chemical reaction

L-glutamine + 2-oxoglutarate + NADPH + H⁺

\rightleftharpoons 2 L-glutamate + NADP⁺

Thus, the four substrates of this enzyme are L-glutamine, 2-oxoglutarate (α-ketoglutarate), NADPH, and H⁺, whereas the two products are L-glutamate and NADP⁺.

This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-NH2 group of donors with NAD+ or NADP+ as acceptor. This enzyme participates in glutamate metabolism and nitrogen metabolism. It has 5 cofactors: FAD, Iron, FMN, Sulfur, and Iron-sulfur.

It occurs in bacteria and plants but not animals, and is important as it provides glutamate for the glutamine synthetase reaction.^{[1] [2]}

Nomenclature

The systematic name of this enzyme class is L-glutamate:NADP+ oxidoreductase (transaminating). Other names in common use include:

• glutamate (reduced nicotinamide adenine dinucleotide phosphate), synthase,
• glutamate synthase (NADPH),
• glutamate synthetase (NADP),
• glutamine amide-2-oxoglutarate aminotransferase (oxidoreductase, NADP),
• glutamine-ketoglutaric aminotransferase,
• L-glutamate synthase,
• L-glutamate synthetase,
• L-glutamine:2-oxoglutarate aminotransferase, NADPH oxidizing,
• NADPH-dependent glutamate synthase,
• NADPH-glutamate synthase, and
• NADPH-linked glutamate synthase.

Structural studies

As of late 2007, only one structure has been solved for this class of enzymes, with the PDB accession code .

See also

• Glutamate synthase (NADH)
• Glutamate synthase (ferredoxin)

Further reading

• Miller RE, Stadtman ER . 1972 . Glutamate synthase from Escherichia coli. An iron-sulfide flavoprotein . J. Biol. Chem. . 247 . 7407 - 19 . 4565085 . 22 .
• Tempest DW, Meers JL, Brown CM . 1970 . Synthesis of glutamate in Aerobacter aerogenes by a hitherto unknown route . Biochem. J. . 117 . 405 - 7 . 5420057 . 2 . 10.1042/bj1170405 . 1178874 .

Notes and References

1. Temple SJ, Vance CP, Gantt JS . 1998 . Glutamate synthase and nitrogen assimilation . Trends in Plant Science . 3 . 2 . 51–56 . 10.1016/S1360-1385(97)01159-X.
2. Vanoni MA, Curti B . Structure-function studies of glutamate synthases: a class of self-regulated iron-sulfur flavoenzymes essential for nitrogen assimilation . IUBMB Life . 60 . 5 . 287–300 . May 2008 . 18421771 . 10.1002/iub.52 . 33617681 . free .