| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 6291981 | Experimental Parasitology | 2012 | 6 Pages |
Phosphofructokinase (PFK-1) activity was examined in L3 and adult Teladorsagia circumcincta, both of which exhibit oxygen consumption. Although activities were higher in the adult stage, the kinetic properties of the enzyme were similar in both life cycle stages. T. circumcincta PFK-1 was subject to allosteric inhibition by high ATP concentration, which increased both the Hill coefficient (from 1.4 ± 0.2 to 1.7 ± 0.2 in L3s and 2.0 ± 0.3 to 2.4 ± 0.4 in adults) and the K½ for fructose 6 phosphate (from 0.35 ± 0.02 to 0.75 ± 0.05 mM in L3s and 0.40 ± 0.03 to 0.65 ± 0.05 mM in adults). The inhibitory effects of high ATP concentration could be reversed by fructose 2,6 bisphosphate and AMP, but glucose 1,6 bisphosphate had no effect on activity. Similarly, phosphoenolpyruvate had no effect on activity, while citrate, isocitrate and malate exerted mild inhibitory effects, but only at concentrations exceeding 2 mM. The observed kinetic properties for T. circumcincta PFK-1 were very similar to those reported for purified Ascaris suum PFK-1, though slight differences in sensitivity to ATP concentration suggests there may be subtle variations at the active site. These results are consistent with the conservation of properties of PFK-1 amongst nematode species, despite between species variation in the ability to utilise oxygen.
Graphical abstractDownload full-size imageHighlights⺠Phosphofructokinase-1 (PFK1) was examined in the nematode Teladorsagia circumcincta. ⺠Kinetic properties were similar in infective larvae and adult worms. ⺠The enzyme was activated by AMP and fructose 2,6-bisphosphate. ⺠High [ATP] inhibited PFK1 but citrate, isocitrate and malate had only mild effects. ⺠Overall, T. circumcincta PFK1 has similar kinetic properties to Ascaris suum PFK1.
