Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.4.1.2 (glutamate dehydrogenase)
 4,380 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A proteome survey and MS analysis were conducted to investigate glucose metabolism in Fusobacterium varium, a butyrate-producing constituent of the indigenous human gut microflora. The bacterium was capable of catabolizing glucose as the main energy source via the Embden-Meyerhof-Parnas pathway. 2-DE analyses revealed that the apparent concentrations of the six identified glycolytic enzymes (pyruvate kinase, enolase, glucose-6-phosphate isomerase, phosphoglycerate kinase, triosephosphate isomerase, and glyceraldehyde-3-phosphate dehydrogenase) were specifically increased in response to the presence of glucose in the chemically defined minimal growth medium, and did not diminish when the medium was additionally supplemented with L-glutamate, an amino acid readily fermented by members of the Fusobacterium genus. A substrate pool depletion study revealed that the sugar, and not the amino acid, is the more efficient growth substrate. Both proteomics and substrate pool depletion studies revealed that F. varium can simultaneously utilize both glucose and L-glutamate as energy sources. Enzymes involved in L-glutamate metabolism were also identified, including an NAD-dependent glutamate dehydrogenase and two enzymes of the methylaspartate pathway of L-glutamate catabolism (glutamate mutase and methylaspartate ammonia-lyase). Their apparent intracellular concentrations were elevated when the bacterium was cultured in media supplemented with excess L-glutamate. Our observation that the apparent concentrations of specific proteins were elevated in response to a particular growth substrate supplied as an energy source provides the first evidence for the presence of a nutrient-responsive mechanism governing intracellular protein concentration in F. varium.
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PMID:Proteomic investigation of glucose metabolism in the butyrate-producing gut anaerobe Fusobacterium varium. 1746 38

The butyrate-producing anaerobe Fusobacterium varium is an integral constituent of human gut microflora. Unlike many gut microorganisms, F. varium is capable of fermenting both amino acids and glucose. Although F. varium has been implicated in beneficial as well as pathological bacterium-host interactions, its genome has not been sequenced. To obtain a better understanding of the metabolic processes associated with amino acid fermentation by F. varium, we used a gel-based proteomic approach to examine the changes in the soluble proteome accompanying the utilization of eight different growth substrates: glucose, L- and D-glutamate, L-histidine, L- and D-lysine, and L- and D-serine. Using LC-MS/MS to analyze approximately 25% of the detected protein spots, we were able to identify 47 distinct proteins. While the intracellular concentrations of enzymes characteristic of a catabolic pathway for a specific amino acid were selectively increased in response to the presence of an excess of that amino acid in the growth medium, the concentrations of the core acetate-butyrate pathway enzymes remained relatively constant. Our analysis revealed (i) high intracellular concentrations of glutamate mutase and beta-methylaspartate ammonia-lyase under all growth conditions, underscoring the importance of the methylaspartate pathway of glutamate catabolism in F. varium (ii) the presence of two enzymes of the hydroxyglutarate pathway of glutamate degradation in the proteome of F. varium ((R)-2-hydroxyglutaryl-CoA dehydratase and NAD-specific glutamate dehydrogenase) specifically when L-glutamate was the main energy source (iii) the presence of genes in the genome of F. varium encoding each of the enzymes of the hydroxyglutarate pathway (iv) the presence of both L- and D-serine ammonia-lyases (dehydratases) which permit F. varium to thrive on either L- or D-serine, respectively, and (v) the presence of aspartate-semialdehyde dehydrogenase and dihydrodipicolinate synthase, consistent with the ability of F. varium to synthesize meso-2,6-diaminopimelic acid as a component of its peptidoglycan. Proteins involved in other cellular processes, including oxidation-reduction reactions, protein synthesis and turnover, and transport were also identified.
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PMID:Proteomic investigation of amino acid catabolism in the indigenous gut anaerobe Fusobacterium varium. 1854 50