Nucleoside triphosphate metabolism in the muscle tissue of Ascaris lumbricoides (Nematoda)

Barrett, John

doi:10.1016/0020-7519(73)90119-7

Cited by 15 publications

(4 citation statements)

References 27 publications

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“…In the present study, K i values for GMP and IMP were higher than those for GTP and ITP. Since physiological levels of GMP and IMP are reportedly below detectable levels in helminths (Senft et al 1972; Barrett, 1973), hence, these molecules, with their high K i values and low physiological concentrations, are not the likely candidates for PEPCK regulation in vivo .…”

Section: Discussionmentioning

confidence: 99%

Purification and characterization of phosphoenolpyruvate carboxykinase fromRaillietina echinobothrida, a cestode parasite of the domestic fowl

et al. 2012

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Phosphoenolpyruvate carboxykinase (PEPCK, EC 4.1.1.32) is an essential regulatory enzyme of glycolysis in helminths in contrast to its role in gluconeogenesis in their host. Previously we have reported that phytochemicals from Flemingia vestita (Family: Fabaceae), genistein in particular, have vermifugal action and are known to affect carbohydrate metabolism in the cestode, Raillietina echinobothrida. In order to determine the functional differences of PEPCK from the parasite and its avian host (Gallus domesticus), we purified the parasite enzyme apparently to homogeneity, and characterized it. The native PEPCK is a monomer with a subunit molecular weight of 65 kDa. The purified enzyme displayed standard Michaelis-Menten kinetics with Km value of 42·52 μM for its substrate PEP. The Ki for the competitive inhibitors GTP, GMP, ITP and IMP for the carboxylation reaction were determined and discussed. In order to identify putative modulators from plant sources, phytochemicals from F. vestita and Stephania glabra were tested on the purified PEPCK, which resulted in alteration of its activity. From our results, we hypothesize that PEPCK may be a potential target site for anthelmintic action.

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Section: Discussionmentioning

confidence: 99%

Purification and characterization of phosphoenolpyruvate carboxykinase fromRaillietina echinobothrida, a cestode parasite of the domestic fowl

et al. 2012

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“…Possibly, in their sheltered environment, parasites are not subject to sudden energy demands, or they may be able to accelerate their metabolism sufficiently quickly that a reserve of high energy phosphate is not necessary. Alternatively, these helminths may use some other method of maintaining their ATP/ADP ratio and the myokinase reaction, for example, could provide a means of temporarily restoring ATP levels by rephosphorylation of part of the ADP (Barrett, 1973). The muscles of parasitic helminths may represent an extreme type and in many ways they resemble vertebrate smooth muscle, a tissue which also has a very low phosphagen content.…”

Section: Resultsmentioning

confidence: 99%

“…A number of parasitic helminths are extremely unusual in that they possess no detectable phosphagens. At the most, only traces of phosphagen occur in adult Fasciola hepatica and Hymenolepis diminuta and in the adult and larva of Ascaris lumbricoides (Rogers & Lazarus, 1949;Fisherova & Kubistova, 1968;Barrett, 1973). Using the isotopic assay of Leech, Beis & Newsholme (1978) traces of arginine phosphotransferase activity were found in the muscle tissue of A. lumbricoides (Leech & Barrett, unpublished observations), but the activity is so low (less than 1 /tmole/min/g fresh weight) that it is difficult to see how it could be of physiological significance.…”

Section: Ph8-5mentioning

confidence: 99%

A novel phosphagen phosphotransferase in the plerocercoids ofSchistocephalus solidus(Cestoda: Pseudophyllidea)

Barrett

Lloyd

1981

Parasitology

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SUMMARYNeither phosphagens nor phosphagen phosphotransferase activity could be detected in Fasciola hepatica, Hymenolepis diminuta, Moniezia expansa or in the plerocercoids of Ligula intestinalis. The plerocercoids of Schistocephalus solidus, however, possess an active taurocyamine phosphotransferase, although it too contains no detectable phosphagens. The taurocyamine phosphotransferase of S. solidus has an absolute requirement for a divalent metal ion and ATP could not be replaced by ITP, GTP, CTP, or UTP as the phosphate donor. The role of phosphagens in helminths is discussed.

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“…Another ' bacterial type ' enzyme found in parasitic helminths is nucleoside diphosphate kinase. This enzyme occurs in particularly high levels in the cytoplasm of those helminths that have a partial reverse TCA cycle (Barrett, 1973). These are parasites, such as adult Ascaris, in which phosphoenolpyruvate is converted to oxaloacetate via phosphoenolpyruvate carboxykinase (PEPcarboxykinase).…”

Section: A T a B O L I C P A T H W A Y Smentioning

confidence: 99%

Forty years of helminth biochemistry

Barrett

2009

Parasitology

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This review describes some of the developments in helminth biochemistry that have taken place over the last 40 years. Since the early 1970s the main anabolic and catabolic pathways in parasitic helminths have been worked out. The mode of action of the majority of anthelmintics is now known, but in many cases the mechanisms of resistance remain elusive. Developments in helminth biochemistry have depended heavily on developments in other areas. High throughput methods such as proteomics, transcriptomics and genome sequencing are now generating vast amounts of new data. The challenge for the future is to interpret and understand the biological relevance of this new information.

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Nucleoside triphosphate metabolism in the muscle tissue of Ascaris lumbricoides (Nematoda)

Cited by 15 publications

References 27 publications

Purification and characterization of phosphoenolpyruvate carboxykinase fromRaillietina echinobothrida, a cestode parasite of the domestic fowl

Purification and characterization of phosphoenolpyruvate carboxykinase fromRaillietina echinobothrida, a cestode parasite of the domestic fowl

A novel phosphagen phosphotransferase in the plerocercoids ofSchistocephalus solidus(Cestoda: Pseudophyllidea)

Forty years of helminth biochemistry

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