Glutamate dehydrogenase
From Proteopedia
FunctionGlutamate dehydrogenase (GLDH) catalyzes the reversible conversion of glutamate to α-ketoglutarate and ammonium. The ammonia is removed via the urea cycle. NAD or NADP is a cofactor in GLDH activity. NAD is a cofactor in the forward reaction while NADP is a cofactor in the reverse reaction. GLDH is regulated by the cell’s energy state. ATP and GTP inhibit the enzyme while ADP, GDP and leucine positively enhance it[1]. Glutamate dehydrogenase 1 (GLDH1) catalyzes the deamination of glutamate to 2-oxoglutarate and ammonium. GLDH1 is regulated in the same manner as GLDH[2]. See also Citric Acid Cycle. RelevanceElevated GLDH values in blood serum indicate liver malfunction[3]. DiseaseMutations in GLDH1 are associated with familial hyperinsulinism[4]. Structural highlightsThe biological assembly of GLDH from Clostridium symbiosum is homohexamer. The glutamate binding pocket of GLDH is in a cleft between the two domains of the enzyme with residue D165 serving as a general base and a protein-bound water molecule as the attacking nucleophile [5]. Water molecules are shown as red spheres. 3D structures of glutamate dehydrogenaseGlutamate dehydrogenase 3D structures
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References
- ↑ FRIEDEN C. GLUTAMATE DEHYDROGENASE. VI. SURVEY OF PURINE NUCLEOTIDE AND OTHER EFFECTS ON THE ENZYME FROM VARIOUS SOURCES. J Biol Chem. 1965 May;240:2028-35. PMID:14299621
- ↑ Smith TJ, Schmidt T, Fang J, Wu J, Siuzdak G, Stanley CA. The structure of apo human glutamate dehydrogenase details subunit communication and allostery. J Mol Biol. 2002 May 3;318(3):765-77. PMID:12054821 doi:10.1016/S0022-2836(02)00161-4
- ↑ Van Waes L, Lieber CS. Glutamate dehydrogenase: a reliable marker of liver cell necrosis in the alcoholic. Br Med J. 1977 Dec 10;2(6101):1508-10. PMID:589307
- ↑ Yorifuji T, Muroi J, Uematsu A, Hiramatsu H, Momoi T. Hyperinsulinism-hyperammonemia syndrome caused by mutant glutamate dehydrogenase accompanied by novel enzyme kinetics. Hum Genet. 1999 Jun;104(6):476-9. PMID:10453735
- ↑ Stillman TJ, Baker PJ, Britton KL, Rice DW. Conformational flexibility in glutamate dehydrogenase. Role of water in substrate recognition and catalysis. J Mol Biol. 1993 Dec 20;234(4):1131-9. PMID:8263917 doi:http://dx.doi.org/10.1006/jmbi.1993.1665
