SUMMARY-Some properties of phosphotriesterase activity derived from the earthworm, Eisenia andrei was investigated This activity appeared to be highly polarized toward intestinal tissues. Epithelial tissue represented the highest PTE activity The nati...
SUMMARY-Some properties of phosphotriesterase activity derived from the earthworm, Eisenia andrei was investigated This activity appeared to be highly polarized toward intestinal tissues. Epithelial tissue represented the highest PTE activity The native molecular weight of earthworm PTE was estimated at 260 kDa and isoelectric point appeared to be about 4. This enzyme activity showed basic optimum at around pH 9. The earth worm PTE is considered to have relatively low substrate affinity for paraoxon, with Km value in the millimolar range. The presence of EGTA and EDTA completely abolished the activity and replacement of Ca^2+ ion restored lost activity over 95%, suggesting that Ca^2+ ion is essential to maintain the activity. In addition, the hydrolysis of paraoxon was inhibited by sulfhydry1 reagents, suggesting that sulfhydry1 group is involved in catalysis