Effect of iodoacetic acid on Acanthoscelides obtectus amylase stability

Abstract

Research 017 the amylases from the gut of the insect pest Acanthoscelides obtectus was studied using purified enzymes. The purification procedures resulted in low recoveries of enzyme because of the degradative action of insect-gut proteinases. To study the inhibition effects of proteinases 017 amylase stability, enzymes of whole larvae homogenates of Acanthoscelieles obtectus were extracted with 0.85 % Na CI solution containing 3, 10 and 15 mM of iodoacetie acid. The extracts were assayed for proteinase and amylase activity against the substrates. azocasein anel starch, respectively. in 100 mM sodium acetate buffer (pH 5,4) containing 0,1 mM CaCI2 anel 38 mM NaCI over a 48 h-period at 4 °C. The result showed that iodoacetic acid at a concentration of 3 mM did not interfere with the amylase activity. However. the proteinase activity was reduced by some 50% at the same eoncentration eluring 24 h. When 10 and 15 mM ioeloacetic acid were used, the proteinase activity decreased by 70 %, while the amylase adivity was reduced by 80 and 95 %, respectively.