Preview

PDF Not available 360Kb

Nematodes, like other species, derive much of the energy for cellular processes from mitochondrial pathways including the TCA cycle. Previously, we have shown L₃ Teladorsagia 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 L₃ T. 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 L₃ T. circumcincta. While there may subtle variations in enzyme properties, particularly for citrate synthase, the control points for the TCA cycle in L₃ T. circumcincta are probably similar to those in the tissues of their host species.

Item Type:	Refereed Article
Keywords:	TCA cycle, nematode, citrate synthase, aconitase, isocitrate dehydrogenase, alpha-ketoglutarate dehydrogenase, Teladorsagia circumcincta
Research Division:	Biological Sciences
Research Group:	Biochemistry and Cell Biology
Research Field:	Enzymes
Objective Division:	Animal Production and Animal Primary Products
Objective Group:	Livestock Raising
Objective Field:	Sheep - Meat
Author:	Brown, S (Dr Simon Brown)
ID Code:	75729
Year Published:	2011
Web of Science® Times Cited:	3
Deposited By:	Health Sciences A
Deposited On:	2012-02-13
Last Modified:	2013-02-05
Downloads:	1 View Download Statistics