Tricarboxylic acid cycle enzymes in the plerocercoid of Ligula intestinalis (Cestoda: Pseudophyllidea).

All enzymes of the tricarboxylic acid cycle are present in subcellular fractions of the plerocercoid of Ligula intestinalis but the low activity of aconitase and malate dehydrogenase in the forward direction suggests that the complete cycle may be of questionable importance to the parasite. As in other helminths and intertidal molluscs, succinate, formed via a partial reversal of the tricarboxylic acid cycle, is a major end-product of anaerobic glucose degradation.