Effect of Different Compounds on Midgut α-Amylase Activity of the Mediterranean Flour Moth, Anagasta kuehniella (Zeller, 1879) (Lep., Pyralidae)

In this investigation، effects of different compounds were evaluated on midgut alpha-amylase activity in male and female fifth in stars of the Mediterranean flour moth. Enzyme specific activity measured using a specific diagnostic kit for alpha-amylase. Total protein in enzyme samples was determined by Bradford''s method. The effects of different degrees of ethanol (0، 25، 50، 75، 85، and 95%) and different concentrations of 0، 1، 2، 3، 4، and 5 mM of NaCl، EDTA، Tris، magnesium nitrate، and potassium phosphate were studied on larval midgut alpha-amylase. The effect of ethanol on enzyme activity was significantly different in male and female larvae and maximum enzyme inhibition occurred by 96% alcohol. Enzyme activity was significantly different in various concentrations of NaCl and it was decreased as NaCl concentration increased. Enzyme activity decreased with increasing SDS concentration and the most activity was observed in male and female larvae at the concentration of 1 mM. The concentration of 5 mM had the lowest activity levels. The effect of different concentrations of EDTA on enzyme activity in female larvae was significantly different but there was no significant difference in males. Different concentrations of Tris، showed a significant effect on enzyme activity of both sexes and enzyme activity decreased due to the increasing of Tris concentration. There was a significant difference among enzyme activities in different concentrations of magnesium nitrate، and enzyme activity decreased when the concentration increased. Enzyme activities in different concentrations of potassium phosphate showed a significant difference and increased due to the increase of concentration from 1 up to 5 mM. Having good understanding about the mode of action of different compounds on alpha-amylases can help us to identify the enzyme inhibitors and their application in pest control.