Proteolytic Activity of Lectins from the Nitrogen-Fixing Bacterium Bacillus polymyxa

Two lectins (LI and LII) stripped from the surface of Bacillus polymyxa1460 cells were found to possess proteolytic activity, which was associated with their hemagglutinating activity. The inhibition of the hemagglutinating activity of lectins by specific carbohydrate haptens changed their enzyme activities. The inhibition of hemagglutinating activity by glucuronic acid or fructose 1,6-diphosphate decreased the proteolytic activities of both lectins, whereas the blocking of this activity with D-glucosamine or D-galactosamine increased the proteolytic activity of LII. The molecules of the B. polymyxalectins are suggested to contain two active centers responsible for hemagglutinating and proteolytic activities.