Glutamate metabolism

Glutamate and glutamine are non-essential amino acids in Coccidians including Neospora caninum and Toxoplasma gondii and in Plasmodium species as in humans. P. falciparum, T. gondii and N. caninum possess both NAD+-specific (1.4.1.2) and NADP+-specific (1.4.1.4, 2 isoforms in P. falciparum and 1 in T. gondii and N. caninum) glutamate dehydrogenases which catalyse reversible conversion of glutamate to 2-oxoglutarate. The metabolic pathway in MPMP (http://sites.huji.ac.il/malaria/maps/glutamatemetpath.html) is extended for Toxoplasma and Neospora as they possess 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 N. caninum gene models as in T. gondii. The genes encoding the enzymes glutamate 5-kinase and glutamyl phosphate reductase are absent in P. falciparum genome.

 

Enzyme EC Number Gene id
Glutamate-5-semialdehyde dehydrogenase 1.2.1.41 NCLIV_036210
Glutamate dehydrogenase 1.4.1.2 NCLIV_065590
Glutamate dehydrogenase 1.4.1.4 NCLIV_000130
Pyrroline-5-carboxylate reductase 1.5.1.2 NCLIV_035400
Pyrroline-5-carboxylate reductase 1.5.1.2 NCLIV_050390
Glutaminyl-peptide cyclotransferase 2.3.2.5 NCLIV_028340
Aspartate transaminase 2.6.1.1 NCLIV_064760
Hexosephosphate aminotransferase 2.6.1.16 NCLIV_031610
Glutamate 5-kinase 2.7.2.11 NCLIV_040220
Glutamyl-tRNA synthetase 6.1.1.17 NCLIV_017290
Glutamyl-tRNA synthetase 6.1.1.17 NCLIV_024090
Glutaminyl-tRNA synthetase 6.1.1.18 NCLIV_062220
Glutaminyl-tRNA synthetase 6.1.1.18 NCLIV_062230
L-glutamate ammonia ligase 6.3.1.2 NCLIV_034160
g-Glutamylcysteine synthetase 6.3.2.2 NCLIV_032550
Carbamoyl-phosphate synthase (Glu synthesizing) 6.3.5.5 NCLIV_052220
Glutamyl-tRNA(Gln) amidotransferase 6.3.5.7 NCLIV_033440

 

List of genes annotated as tRNA-Glu in N. caninum genome

 

NC_LIV_tRNA_080006 NC_LIV_tRNA_090002 NC_LIV_tRNA_100009 NC_LIV_tRNA_100019
NC_LIV_tRNA_100020 NC_LIV_tRNA_110007 NC_LIV_tRNA_120008 NC_LIV_tRNA_130006
NC_LIV_tRNA_140003      

 

List of genes annotated as tRNA-Gln in N. caninum genome

 

NC_LIV_tRNA_010007 NC_LIV_tRNA_040001 NC_LIV_tRNA_110001 NC_LIV_tRNA_110008
NC_LIV_tRNA_130009      

 

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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