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

Simcock, D.C., Walker, L.R., Pedley, K.C., Simpson, H.V., and Brown, S. (2012) Phosphoenolpyruvate metabolism in Teladorsagia circumcincta: a critical junction between aerobic and anaerobic metabolism. Experimental Parasitology, 132 (2). pp. 267-273.

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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.

Item ID: 35754
Item Type: Article (Research - C1)
ISSN: 1090-2449
Keywords: phosphoenolpyruvate carboxykinase, pyruvate kinase, nematode, Teladorsagia circumcincta, energy metabolism
Funders: Beef and Lamb New Zealand, Agricultural and Marketing Research and Development Trust (AGMARDT)
Date Deposited: 15 Oct 2014 16:48
FoR Codes: 06 BIOLOGICAL SCIENCES > 0601 Biochemistry and Cell Biology > 060107 Enzymes @ 50%
07 AGRICULTURAL AND VETERINARY SCIENCES > 0707 Veterinary Sciences > 070708 Veterinary Parasitology @ 50%
SEO Codes: 97 EXPANDING KNOWLEDGE > 970106 Expanding Knowledge in the Biological Sciences @ 50%
97 EXPANDING KNOWLEDGE > 970107 Expanding Knowledge in the Agricultural and Veterinary Sciences @ 50%
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