Antibodies to the glutamate dehydrogenase of<i>Plasmodium falciparum</i>

Ling, Irene T.; Cooksley, Susan; Bates, Paul A.; Hempelmann, Ernst; Wilson, Robert

doi:10.1017/s0031182000064088

Cited by 17 publications

(12 citation statements)

References 19 publications

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“…A previous study, using cross-reacting antibodies, suggested that the parasites possess a cytosolic GDH protein without distinguishing which of the three GDH proteins is detected by the antibodies [52]. It was demonstrated here that GDHa-GFP, expressed episomally in P. falciparum , localizes exclusively to the parasite's cytosol while there is no GFP fluorescence present in the mitochondrion or the apicoplast.…”

Section: Discussionmentioning

confidence: 63%

Plasmodium falciparum glutamate dehydrogenase a is dispensable and not a drug target during erythrocytic development

Storm

Perner

Aparicio

et al. 2011

Malar J

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BackgroundPlasmodium falciparum contains three genes encoding potential glutamate dehydrogenases. The protein encoded by gdha has previously been biochemically and structurally characterized. It was suggested that it is important for the supply of reducing equivalents during intra-erythrocytic development of Plasmodium and, therefore, a suitable drug target.MethodsThe gene encoding the NADP(H)-dependent GDHa has been disrupted by reverse genetics in P. falciparum and the effect on the antioxidant and metabolic capacities of the resulting mutant parasites was investigated.ResultsNo growth defect under low and elevated oxygen tension, no up- or down-regulation of a number of antioxidant and NADP(H)-generating proteins or mRNAs and no increased levels of GSH were detected in the D10Δgdha parasite lines. Further, the fate of the carbon skeleton of [13C] labelled glutamine was assessed by metabolomic studies, revealing no differences in the labelling of α-ketoglutarate and other TCA pathway intermediates between wild type and mutant parasites.ConclusionsFirst, the data support the conclusion that D10Δgdha parasites are not experiencing enhanced oxidative stress and that GDHa function may not be the provision of NADP(H) for reductive reactions. Second, the results imply that the cytosolic, NADP(H)-dependent GDHa protein is not involved in the oxidative deamination of glutamate but that the protein may play a role in ammonia assimilation as has been described for other NADP(H)-dependent GDH from plants and fungi. The lack of an obvious phenotype in the absence of GDHa may point to a regulatory role of the protein providing glutamate (as nitrogen storage molecule) in situations where the parasites experience a limiting supply of carbon sources and, therefore, under in vitro conditions the enzyme is unlikely to be of significant importance. The data imply that the protein is not a suitable target for future drug development against intra-erythrocytic parasite development.

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Section: Discussionmentioning

confidence: 63%

Plasmodium falciparum glutamate dehydrogenase a is dispensable and not a drug target during erythrocytic development

Storm

Perner

Aparicio

et al. 2011

Malar J

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“…fakiparum glutamate dehydrogenase. In spite of its relative abundance and its physiological importance (Walter et al, 1974), enzymically active plasmodia] GDH has not been purified to homogeneity before; the isolation of this protein as an antigen was achieved in the elegant study of Ling et al (1986). Since we were primarily interested in GDH only as a stable marker enzyme of the parasite compartment, the enzyme was not studied in detail; some basic enzyme kinetic data of purified P. ,falciparum GDH are, however, summarized in Table 2.…”

Section: Resultsmentioning

confidence: 99%

“…All data rcfer to the pH optima o f 8.0 and 7.0, respectively. V for the reverse reaction was 22 U/mg (see Table 1 (Ling et al, 1986;Vander Jagt et al, 1989). The remarkable heat stability of the enzyme has been mentioned in khe previous section.…”

Section: Resultsmentioning

confidence: 99%

Glutathione Reductase and Glutamate Dehydrogenase of Plasmodium Falciparum, The Causative Agent of Tropical Malaria

Krauth‐Siegel

Müller

Lottspeich

et al. 1996

European Journal of Biochemistry

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The use of glutathione reductase inhibitors in chemotherapy is the raison d'&tre for this study. Two enzymes were purified to homogeneity from the intraerythrocytic malarial parasite Plasmodium falciparum : glutathione disulfide reductase, an antioxidative enzyme, which appears to play an essential role for parasite growth and differentiation, and glutamate dehydrogenase, an enzyme not occurring in the host erythrocyte. The two proteins were copurified and separated by gel electrophoresis with yields of approximately 20%. Malarial glutathione reductase, a homodimer of 110 kDa with a pH optimum of 6.8 and a high preference for NADPH over NADH, was shown to contain FAD as its prosthetic group. The N-terminal sequence, VYDLIVIGGGSGGMA, which can be aligned with residues 20-34 of human glutathione reductase, represents the first /j strand and the diphosphate-fixing helix of the FAD domain. Glutamate dehydrogenase was confirmed as a hexamer with blocked N-termini; it is an enzyme that is highly specific for NADP and NADPH. The copurification of the proteins and the potential of I? ,fulcipurunz glutathione reductase as a drug target are discussed.

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“…Our results, obtained under reducing conditions, led to the interpretation that native GDH(NADP + ) could correspond to a protein consisting of 4 subunits. GDH (NADP + ) shows no cross-reaction with the enzyme of mammals (14), but rather with Proteus spp.…”

Section: Discussionmentioning

confidence: 99%

Characterization of Plasmodium falciparum glutamate dehydrogenase-soluble antigen

Rodrı́guez-Acosta

Domínguez

Aguilar

et al. 1998

Braz J Med Biol Res

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The major aim of this study was to characterize a soluble Plasmodium falciparum antigen from the plasma of malaria-infected humans and Plasmodium falciparum culture supernatants, using immunoabsorbent techniques and Western blotting. An Mr 60-kDa protein was isolated from the plasma of patients with Plasmodium falciparum malaria by affinity chromatography using rabbit anti-Proteus spp GDH(NADP + ) serum as ligand. This protein, present in plasma of patients with acute Plasmodium falciparum infection, in Plasmodium falciparum culture supernatants, and in immune complexes, was tested with Plasmodium falciparum malaria hyperimmune serum from patients living in hyperendemic areas and rabbit anti-Proteus spp GDH(NADP + ) serum prepared in the laboratory. In this report, we describe the results of a study showing that parasite GDH(NADP + ) can be used to detect the presence of Plasmodium falciparum. It appears that this technique permits the chromatographic detection of a Plasmodium falciparum excretion antigen that may be used in the production of monoclonal antibodies to improve immunodiagnostic assays for the detection of antigenemia, and opens the possibility of its use as a non-microscopic screening method.

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Antibodies to the glutamate dehydrogenase ofPlasmodium falciparum

Cited by 17 publications

References 19 publications

Plasmodium falciparum glutamate dehydrogenase a is dispensable and not a drug target during erythrocytic development

Plasmodium falciparum glutamate dehydrogenase a is dispensable and not a drug target during erythrocytic development

Glutathione Reductase and Glutamate Dehydrogenase of Plasmodium Falciparum, The Causative Agent of Tropical Malaria

Characterization of Plasmodium falciparum glutamate dehydrogenase-soluble antigen

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