[Proteolytic activity of lectins from the nitrogen-fixing bacterium Bacillus polymyxa]. / Proteoliticheskaia aktivnost' lektinov azotfiksiruiushchikh bakterii Bacillus polymyxa.

Two lectins (LI and LII) stripped from the surface of Bacillus polymyxa 1460 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. polymyxa lectins are suggested to contain two active centers responsible for hemagglutinating and proteolytic activities.

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 bacterium Bacillus polymyxa 1460, were shown to possess proteolytic activity. A relationship was found between the proteolytic and hemagglutinating activities of the lectins. Blocking of hemagglutinating activity with specific carbohydrate haptens led to significant changes in the enzyme activity of both lectins. When lectin activity was blocked with glucuronic acid and fructose-1, 6-diphosphate, the proteolytic activity of both LI and LII declined, whereas incubation with d-galactosamine and d-glucosamine promoted increases in the proteolytic activity of LII. This study proposes that the molecules of the B. polymyxa lectins may have two centers on their surfaces: one responsible for lectin activity and the other for proteolytic activity.