HEMAGGLUTINATING ACTIVITY OF TRYPSIN INHIBITORS FROM THE SEEDS OF ABELMOSCHUS MOSCHATUS L

A highly stable and potent trypsin inhibitor (AMTI-I) was purified to homogeneity from the seeds of Abelmoschus moschatus, family Malvaceae, following conventional methods of protein purification. AMTI-I exerted strong inhibition towards bovine pancreatic trypsin and it showed moderate inhibition towards elastase. SDS-PAGE analysis, under reducing conditions, indicated the protein consisting of a single polypeptide chain with a apparent molecular mass of 22.4 kDa. The inhibitors, AMTI-I and AMTI-II also isolated and purified from the same source, are unique in that they exhibited hemagglutinating activity towards different erythrocytes. This activity was found to be inhibited by D-galactose only. The lectin activity was stable over a broad pH range (3.0-12.0) and temperatures up to 60oC for 15 min and was also resistant to denaturants. Oxidation of AMTI-I and AMTI-II by sodium metaperiodate or treatment with PNGase F affected their lectin activities. Since trypsin inhibitors and lectins have been shown to provide protection in plants against invading insect pests and pathogens, AMTI-I and AMTI-II possessing both antitryptic and lectin activities may be explored in the agricultural front for developing transgenics after carrying out extensive in vitro studies.