title: Enzymes of the tricarboxylic acid cycle in Ancylostoma ceylanicum and Nippostrongylus brasiliensis.
abstract: Enzymes of the tricarboxylic acid (TCA) cycle and glyoxylate pathway were investigated in adults and infective larvae of Ancylostoma ceylanicum and Nippostrongylus brasiliensis, and their activities were compared with those obtained in rat liver. A complete sequence of enzymes of the TCA cycle, with most of them showing activities quite similar to those in the rat liver homogenate, was detected in adults of both species. All the enzymes except fumarase and malate dehydrogenase were located predominantly in mitochondria where they showed a variable distribution of activities between the soluble and the membranes fractions. Malate dehydrogenase and fumarase were found in both the mitochondria and the 9,000-g supernatant fraction. Succinyl CoA synthetase, which was present in minimum activity, appeared rate limiting. Enzymes of the glyoxylate pathway, particularly isocitrate lyase, seemed to aid the functioning of the Krebs cycle by allowing the formation of succinate from isocitrate. The infective larvae of both species also were found equipped with all the enzymes of the Krebs cycle. Nonetheless, only isocitrate lyase of the glyoxylate pathway could be detected in these parasites.
authors.affiliation: Division of Biochemistry, Central Drug Research Institute, Lucknow, India.
authors.forename: S P
authors.initials: SP
authors.lastname: Singh
authors.forename: J C
authors.initials: JC
authors.lastname: Katiyar
authors.forename: V M
authors.initials: VM
authors.lastname: Srivastava
mesh_terms: D000154:Aconitate Hydratase / Q000378:metabolism; D000722:Ancylostoma / Q000201:enzymology*; D000818:Animals; D002950:Citrate (si)-Synthase / Q000378:metabolism; D002952:Citric Acid Cycle; D005649:Fumarate Hydratase / Q000378:metabolism; D006038:Glyoxylates / Q000378:metabolism; D007521:Isocitrate Dehydrogenase / Q000378:metabolism; D007655:Ketoglutarate Dehydrogenase Complex / Q000378:metabolism; D008099:Liver / Q000201:enzymology; D008291:Malate Dehydrogenase; D009559:Nippostrongylus / Q000201:enzymology*; D051381:Rats; D013385:Succinate Dehydrogenase / Q000378:metabolism; D013389:Succinate-CoA Ligases / Q000378:metabolism
chemical_list: D006038:Glyoxylates; D008291:Malate Dehydrogenase; D007521:Isocitrate Dehydrogenase; D007655:Ketoglutarate Dehydrogenase Complex; D013385:Succinate Dehydrogenase; D002950:Citrate (si)-Synthase; D005649:Fumarate Hydratase; D000154:Aconitate Hydratase; D013389:Succinate-CoA Ligases