Abstract
1. The kinetics and inhibition of ρ-nitrophenylacetate hydrolysis by cytosolic esterases of 1-day old female honey bees, Apis mellifera L., were studied.
2. The calculated values obtained were Km = 2.27x 10−5M and Vmax = 2.48 × 10−8mol/s per mg protein.
3. The inhibition mechanisms examined for four organophosphorus insecticides were highly competitive in nature and based on competitive inhibition coefficients the order of toxicity was naled >dichlorvos>cis-mevinphos = trans-mevinphos.
4. Comparisons are made with the alfalfa leafcutting bee, Megachile rotundata (Fab).