Glutamate metabolism
Glutamate and glutamine are non-essential amino acids in both Toxoplasma gondii and Plasmodium falciparum as in humans. Both organisms possess NAD+-specific (1.4.1.2) and NADP+-specific (1.4.1.4, 2 isoforms in P. falciparum and 1 in T. gondii) glutamate dehydrogenases that catalyse reversible conversion of glutamate to 2-oxoglutarate. The metabolic pathway in MPMP (http://sites.huji.ac.il/malaria/maps/glutamatemetpath.html) is extended here for Toxoplasma as it possesses the capability to de novo synthesise proline from glutamate as in humans [1]. The genes for all the enzymes involved in this process are present in T. gondii gene models. The genes encoding the enzymes glutamate 5-kinase and glutamyl phosphate reductase are absent in P. falciparum genome.
Enzyme | EC Number | Gene id | Protein localisation | Localisation data source |
---|---|---|---|---|
Glutamate-5-semialdehyde dehydrogenase | 1.2.1.41 | TGME49_270550 | Cytosol | Previous publication |
Glutamate dehydrogenase | 1.4.1.2 | TGME49_249390 | Mitochondrion | Previous publication |
Glutamate dehydrogenase | 1.4.1.4 | TGME49_293180 | Cytosol | Previous publication |
Pyrroline-5-carboxylate reductase | 1.5.1.2 | TGME49_236070 | Extracellular? | Previous publication |
Pyrroline-5-carboxylate reductase | 1.5.1.2 | TGME49_271610 | Apicoplast | Previous publication |
Glutaminyl-peptide cyclotransferase | 2.3.2.5 | TGME49_258020 | ||
Aspartate transaminase | 2.6.1.1 | TGME49_248600 | Cytosol | Previous publication |
Hexosephosphate aminotransferase | 2.6.1.16 | TGME49_231350 | Apicoplast | Previous publication |
Glutamate 5-kinase | 2.7.2.11 | TGME49_265010 | ||
Glutamyl-tRNA synthetase | 6.1.1.17 | TGME49_241870 | ||
Glutamyl-tRNA synthetase | 6.1.1.17 | TGME49_263870 | Cytosol | Previous publication |
Glutaminyl-tRNA synthetase | 6.1.1.18 | TGME49_217460 | Cytosol; Mitochondrion | Apiloc; Previous publication |
L-glutamate ammonia ligase | 6.3.1.2 | TGME49_273490 | Cytosol | Previous publication |
gamma-Glutamylcysteine synthetase | 6.3.2.2 | TGME49_232590 | ||
Carbamoyl-phosphate synthase Glu synthesizing | 6.3.5.5 | TGME49_215260 | Cytosol | Previous publication |
Glutamyl-tRNA(Gln) amidotransferase | 6.3.5.7 | TGME49_233838 |
List of genes annotated as tRNA-Glu in T. gondii genome
TGME49_002320 | TGME49_014360 | TGME49_018480 | TGME49_034622 |
TGME49_061550 | TGME49_068440 | TGME49_068450 | TGME49_071891 |
TGME49_111190 | TGME49_111200 |
List of genes annotated as tRNA-Gln in T. gondii genome
TGME49_034617 | TGME49_067110 | TGME49_072220 | TGME49_075820 |
TGME49_102030 | TGME49_105170 | TGME49_115200 |
Sources and fates of metabolites
Substrate | Source pathways | Product | Fate pathways |
---|---|---|---|
D-Fructose-6P | Glycolysis | Oxaloacetate | Pyruvate metabolism, Tricarboxylic acid (TCA) cycle |
2-oxoglutarate | Tricarboxylic acid (TCA) cycle | ||
gamma-glutamylcysteine | Redox metabolism | ||
Glucosamine-6P | Aminosugars metabolism | ||
Carbamoyl-P | Pyrimidine metabolism | ||
L-Proline | Proline metabolism |
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