Enzyme activity of lectins from the nitrogen-fixing soil bacterium Bacillus polymyxa

Lectins LI and LII, localized on the surface of the nitrogen-fixing soil ba cterium Bacillus polymyxa 1460, were shown to possess proteolytic activity. A relationship was found between the proteolytic and hemagglutinating acti vities of the lectins. Blocking of hemagglutinating activity with specific carbohydrate haptens led to significant changes in the enzyme activity of b oth lectins. When lectin activity was blocked with glucuronic acid and fruc tose-1,6-diphosphate, the proteolytic activity of both LI and LII declined, whereas incubation with D-galactosamine and D-glucosamine promoted increas es in the proteolytic activity of LII. This study proposes that the molecul es of the B. polymyxa lectins may have two centers on their surfaces: one r esponsible for lectin activity and the other for proteolytic activity.