Comparison of dextranases for their possible use in eliminating dental plaque.

Dextranases produced by P lilacinum NRRL 896 and NRRL 895 and by P funiculosum NRRL 1768 were studied for their possible incorporation into a dental plaque elimination system. The following properties of the enzymes were compared: effect of the pH level on the activity and the stability of the enzymes on the acid side of the pH range; molecular weight; affinity to Sephadex G-25 which served as a model for insoluble dextran in plaques; and the extent of hydrolytic action on dextrans containing alpha-1,3, alpha-1,4 and alpha-1,6 bonds in various proportions. The enzyme of P funiculosum NRRL 1768 certainly has its limitations as a plaque-degrading enzyme, for example, diminished activity at a high pH level and lack of activity on alpha-1,3 bonds. However, from our studies, and from a survey of the relevant literature with respect to the aforementioned properties in other dextranases, the enzyme of P funiculosum NRRL 1768 emerges as a suitable choice for incorporation as dextranase, possibly together with other enzymes, into an enzymatic dental plaque elimination system.