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Phosphoenolpyruvate metabolism in Teladorsagia circumcincta: a critical junction between aerobic and anaerobic metabolism

journal contribution
posted on 2023-05-17, 15:45 authored by Simcock, DC, Walker, LR, Pedley, KC, Simpson, HV, Brown, S
Nematodes which have adapted to an anaerobic lifestyle in their adult stages oxidise phosphoenolpyruvate (PEP) to oxaloacetate rather than pyruvate as the final product of glycolysis. This adaptation involves selective expression of the enzyme phosphoenolpyruvate carboxykinase (PEPCK), instead of pyruvate kinase (PK). However, such adaptation is not absolute in aerobic nematode species. We have examined the activity and kinetics of PEPCK and PK in larvae (L3) and adults of Teladorsagia circumcincta, a parasite known to exhibit oxygen uptake. Results revealed that PK and PEPCK activity existed in both L3s and adults. The enzymes had differing affinity for nucleotide diphosphates: while both can utilise GDP, only PK utilised ADP and only PEPCK utilised IDP. In both life cycle stages, enzymes showed similar affinity for PEP. PK activity was predominant in both stages, although activity of this enzyme was lower in adults. When combined, both the activity levels and the enzyme kinetics showed that pyruvate production is probably favoured in both L3 and adult stages of T. circumcincta and suggest that metabolism of PEP to oxaloacetate is a minor metabolic pathway in this species.


Publication title

Experimental Parasitology








School of Health Sciences


Academic Press

Place of publication

3251 Riverport Ln, Maryland Heights, MO 63043, USA

Rights statement

Copyright 2012 Elsevier Inc.

Repository Status

  • Restricted

Socio-economic Objectives

Sheep for meat

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    University Of Tasmania