Submitted to: Russian Journal of Nematology
Publication Type: Abstract Only
Publication Acceptance Date: June 6, 2001
Publication Date: N/A
Technical Abstract: Endogenous molecules involved with nematode metabolism have potential as leads to the discovery of new control strategies for plant parasitic nematodes. Aminopeptidases are known to be associated with regulatory peptide metabolism in invertebrates, including animal parasitic nematodes. Aminopeptidase-like activities have been examined in crude extracts of Caenorhabditis elegans and Heterodera glycines J2. Km of the aminopeptidase for the substrate L-alanine-4-nitroanilide (Ala-pNA) was the same for both species, but Vmax was 4-times greater for C. elegans than H. glycines. Other characteristics including pH optima, heat lability and loss of activity after exposure to acetonitrile were similar for the two enzymes. Differences appeared in response to enzyme inhibitors including amastatin. H. glycines aminopeptidase-like activity was more stable at room temperature than that of C. elegans, but more labile to alcohols (ethanol, methanol) than C. elegans activity. Divalent cations (Ca++, Co++, Mg++, Zn++) had little apparent effect on H. glycines aminopeptidase-like activity, but were inhibitory to that in C. elegans. Both H. glycines and C. elegans prefer Ala-pNA as substrate, but differed in their responses to other substrates. C. elegans activity with Arg-, Lys- or Met-pNA ranged between 60 to 80 percent of that with Ala-pNA. With these substrates, H. glycines showed less than 10 percent of Ala-pNA activity. In contrast, H. glycines activity with Pro-pNA was 50 percent of Ala-pNA activity, but in C. elegans activity with Pro-pNA was less than 10 percent of Ala-pNA activity. Such biochemical differences between species may prove to be important in the development of specific molecular control agents such as enzyme inhibitors.