Some Properties of Acetylcholinesterases Partially Purified from Susceptible and Resistant Green Rice Leafhoppers, Nephotettix Cincticeps Uhler (Hemiptera: Deltocephalidae)

Abstract

Properties of acetylcholinesterases (AChE) in the green rice leafhopper were examined using partially purified normal and modified AChEs. The modified enzyme was much less sensitive to inhibition by propoxur and malaoxon than the normal one, but highly sensitive to inhibition by diazoxon. Substrate specificity and effect of pH on activity of the normal enzyme were similar to those of the bovine erythrocyte AChE used as a reference enzyme, but those of the modified AChE were obviously different from those of the other enzymes. On the other hand, difference of the normal and modified AChEs in the Km values of substrates was rather small, i.e., by a factor of less than 2. It may be concluded that the modified AChE alters in a binding site, which is related to the reaction with inhibitors, but different from the site for the intrinsic substrate acetylcholine. © 1980, JAPANESE SOCIETY OF APPLIED ENTOMOLOGY AND ZOOLOGY. All rights reserved.