The tricarboxylic acid cycle in L3Teladorsagia circumcincta: metabolism of acetyl CoA to succinyl CoA

Simcock, D.C., Walker, L.R., Pedley, K.C., Simpson, H.V., and Brown, S. (2011) The tricarboxylic acid cycle in L3Teladorsagia circumcincta: metabolism of acetyl CoA to succinyl CoA. Experimental Parasitology, 128 (1). pp. 68-75.

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Nematodes, like other species, derive much of the energy for cellular processes from mitochondrial pathways including the TCA cycle. Previously, we have shown L3Teladorsagia circumcincta consume oxygen and so may utilise a full TCA cycle for aerobic energy metabolism. We have assessed the relative activity levels and substrate affinities of citrate synthase, aconitase, isocitrate dehydrogenase (both NAD+ and NADP+ specific) and α-ketoglutarate dehydrogenase in homogenates of L3T. circumcincta. All of these enzymes were present in homogenates. Compared with citrate synthase, low levels of enzyme activity and low catalytic efficiency was observed for NAD+ isocitrate dehydrogenase and especially α-ketoglutarate dehydrogenase. Therefore, it is likely that the activity of these to enzymes regulate overall metabolite flow through the TCA cycle, especially when [NAD+] limits enzyme activity. Of the enzymes tested, only citrate synthase had substrate affinities which were markedly different from values obtained from mammalian species. Overall, the results are consistent with the suggestion that a full TCA cycle exists within L3T. circumcincta. While there may subtle variations in enzyme properties, particularly for citrate synthase, the control points for the TCA cycle in L3T. circumcincta are probably similar to those in the tissues of their host species.

Item ID: 35756
Item Type: Article (Research - C1)
ISSN: 1090-2449
Keywords: TCA cycle, nematode, citrate synthase, aconitase, isocitrate dehydrogenase, alpha-ketoglutarate dehydrogenase, Teladorsagia circumcincta
Funders: Meat and Wool 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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