This view shows enzymes only for those organisms listed below, in the list of taxa known to possess the pathway. If an enzyme name is shown in bold, there is experimental evidence for this enzymatic activity.
Synonyms: glutamate biosynthesis from glutamine
|Superclasses:||Biosynthesis → Amino Acids Biosynthesis → Individual Amino Acids Biosynthesis → Glutamate Biosynthesis|
Yeast cells contain 3 pathways for the synthesis of glutamate. Two pathways are mediated by two isoforms of glutamate dehydrogenase, encoded by GDH1 and GDH3 [Moye85][Avendano97]. The third pathway is driven by the combined activities of glutamine synthetase and glutamate synthase, encoded by GLN1 and GLT1, respectively [Benjamin89][Filetici96]. Gln1p catalyzes amination of glutamate to form glutamine; Glt1p then transfers the amide group of glutamine to 2-oxoglutarate, generating two molecules of glutamate. Glutamate synthase, also referred to as GOGAT, is a trimer of three Glt1p subunits. Expression of the GLT1 gene is modulated by glutamate-mediated repression and by Gln3p/Gcn4p-mediated activation, depending upon the availability of nitrogen and glutamate in the medium. In amino acid starvation conditions, GLT1 expression is activated to a moderate degree by Gcn4p [Valenzuela98].
Superpathways: glutamate and glutamine biosynthesis
Avendano97: Avendano A, Deluna A, Olivera H, Valenzuela L, Gonzalez A (1997). "GDH3 encodes a glutamate dehydrogenase isozyme, a previously unrecognized route for glutamate biosynthesis in Saccharomyces cerevisiae." J Bacteriol 179(17);5594-7. PMID: 9287019
Benjamin89: Benjamin PM, Wu JI, Mitchell AP, Magasanik B (1989). "Three regulatory systems control expression of glutamine synthetase in Saccharomyces cerevisiae at the level of transcription." Mol Gen Genet 217(2-3);370-7. PMID: 2570348
Filetici96: Filetici P, Martegani MP, Valenzuela L, Gonzalez A, Ballario P (1996). "Sequence of the GLT1 gene from Saccharomyces cerevisiae reveals the domain structure of yeast glutamate synthase." Yeast 12(13);1359-66. PMID: 8923741
Moye85: Moye WS, Amuro N, Rao JK, Zalkin H (1985). "Nucleotide sequence of yeast GDH1 encoding nicotinamide adenine dinucleotide phosphate-dependent glutamate dehydrogenase." J Biol Chem 260(14);8502-8. PMID: 2989290
Valenzuela98: Valenzuela L, Ballario P, Aranda C, Filetici P, Gonzalez A (1998). "Regulation of expression of GLT1, the gene encoding glutamate synthase in Saccharomyces cerevisiae." J Bacteriol 180(14);3533-40. PMID: 9657994
Boland77: Boland MJ, Benny AG (1977). "Enzymes of nitrogen metabolism in legume nodules. Purification and properties of NADH-dependent glutamate synthase from lupin nodules." Eur J Biochem 79(2);355-62. PMID: 21790
Cogoni95: Cogoni C, Valenzuela L, Gonzalez-Halphen D, Olivera H, Macino G, Ballario P, Gonzalez A (1995). "Saccharomyces cerevisiae has a single glutamate synthase gene coding for a plant-like high-molecular-weight polypeptide." J Bacteriol 177(3);792-8. PMID: 7836314
Esposito05: Esposito S, Guerriero G, Vona V, Di Martino Rigano V, Carfagna S, Rigano C (2005). "Glutamate synthase activities and protein changes in relation to nitrogen nutrition in barley: the dependence on different plastidic glucose-6P dehydrogenase isoforms." J Exp Bot 56(409);55-64. PMID: 15501908
Gregerson93: Gregerson RG, Miller SS, Twary SN, Gantt JS, Vance CP (1993). "Molecular characterization of NADH-dependent glutamate synthase from alfalfa nodules." Plant Cell 5(2);215-26. PMID: 8453303
Hayakawa93: Hayakawa T, Yamaya T, Mae T, Ojima K (1993). "Changes in the Content of Two Glutamate Synthase Proteins in Spikelets of Rice (Oryza sativa) Plants during Ripening." Plant Physiol 101(4);1257-1262. PMID: 12231780
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