Glutamate metabolism

Glutamate and glutamine are non-essential amino acids in both Toxoplasma gondii and Plasmodium falciparum as in humans, whereas glutamine is an essential amino acid utilised from host in Piroplasma species. This is because glutamine synthetase ezyme which catalyses glutamate to glutamine conversion is absent in these Piroplasma species. The favourable ecological niches of these parasites within hosts and the absence of parasitophorous vacuoles provide these parasites with the advantage of their ability to fulfil several amino acid requirements including asparagine, glutamine and proline from the host. The activity of aspartate transaminase enzyme of this pathway was assayed by Kiama et al in Theileria parva schizont and transamination of oxaloacetate with glutamate plays an important role in the carbon metabolism of this parasite [1].

 

Enzyme EC Number Gene id
Glutamate dehydrogenase (NAD-specific) 1.4.1.2 TP04_0883
Glutamate dehydrogenase (NADP-specific) 1.4.1.4 Missing in annotation (Absent)
Glutaminyl-peptide cyclotransferase 2.3.2.5 Missing in annotation (Absent)
Aspartate transaminase 2.6.1.1 TP02_0046
Hexosephosphate aminotransferase 2.6.1.16 TP02_0935
Glutamyl-tRNA synthetase 6.1.1.17 TP01_0727
Glutamyl-tRNA synthetase 6.1.1.17 TP01_1053
Glutaminyl-tRNA synthetase 6.1.1.18 TP02_0322
gamma-Glutamylcysteine synthetase 6.3.2.2 TP03_0084
Carbamoyl-phosphate synthase Glu synthesizing 6.3.5.5 TP03_0048
Glutamyl-tRNA(Gln) amidotransferase 6.3.5.7 TP01_0031

 

List of genes annotated as tRNA-Glu in T. parva genome

 

TP02_0970 TP02_0971 TP05_0054

 

List of genes annotated as tRNA-Gln in T. parva genome

 

TP03_0936 TP03_0937 TP05_0058

 

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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
Glutamine Host 2-oxoglutarate Tricarboxylic acid (TCA) cycle
    gamma-glutamylcysteine Redox metabolism
    Glucosamine-6P Aminosugars metabolism
    Carbamoyl-P Pyrimidine metabolism