Purification of an Alpha - Amylase Inhibitor from Seeds of Little Millet (Panicum sumatrens Roth)

An insect specific alpha-amylase inhibitor (α-Al) from seeds of CO3 variety of little millet (Panicurn surnafrens Roth) was isolated and purified to homogeneity following ammonium sulfate precipitation, successive chromatographic separations on Sephadex G75 and CM- cellulose columns and finally through RP-HPLC. Western blotting using polyclonal antibodies raised against the purified α-Al identified a unique band. The purified protein was found to be a non-glycosylated polypeptide with a molecular weight of 36kD. The isolated inhibitor severely inhibited the larval rnidgut alpha-amylases of tomato fruit borer (Helicoverpa armigera), brinjal shoot and fruit borer (Leucinodes orbonalis) and cucurbit fruit fly (Dacus cucurbitae).