<p class=\"MsoNormal\" style=\"text-align: justify;\"><span style=\"font-size: 12.0pt; line-height: 115%; font-family: \'Times New Roman\',\'serif\';\">&alpha;-amylase inhibitor proteins have inculcated a considerable attention over the past few years on account of their potential effect on the crop pest regarding their importance in natural defense. Their implications in natural protection mechanisms proficiently can be exploited for the routine gene manipulation techniques; hence these genes have been expressed in transgenic seeds to create resistance toward beetles and other insect pests of useful crops. For the wider selection of gene pool, the present study was undertaken to screen four legume tree viz.<em> Cassia tora, Cassia occidentalis, Cassia floribunda, Crotalaria albida</em> for their &alpha;-amylase inhibitor protein content and further used to purify and characterize &alpha;-amylase inhibitor protein(s). The maximum &alpha;-amylase inhibitor activity in crude extract has been found in <em>Cassia tora</em> which was 48.1units/gm. of seeds. The crude extract was then used to purify the &alpha;-amylase inhibitor protein(s). Heat treatment of crude extract at 70<sup>0</sup>C for 30 min increased the specific activity of amylase inhibition of <em>Cassia</em> species total seed protein. Heat treatment of protein extract can confirmed the heat stable character of alpha amylase inhibitor of <em>Cassia</em> species. The heat treated seed extracts were further subjected to ammonium sulphate (20-50%), fractionation, dialysis, gel filteration through sephacryl S-200 and subsequently to ion exchange chromatography through DEAE-Sephadex A-50. After purification steps maximum specific activity has been observed in <em>Cassia occidentalis</em> which was 160.00 units/mg protein followed by<em> Cassia tora</em>. Out of four species of legumes <em>Cassia tora and Cassia albida</em> inhibitor proteins were found to be multimeric, in <em>Cassia occidentalis </em>and<em> Cassia floribunda </em>were monomer.&nbsp; &nbsp;&nbsp;</span></p>