Abstract: A method of producing .alpha.-1, 3-glucanase by introducing a bacterial culture such as Pseudomonas sp. isolate NRRL B-12324 into an aqueous medium containing a "limit glucan" substrate which is greater than 90 percent .alpha.-1, 3-glycosidically linked, then allowing growth to take place to accumulate .alpha.-1, 3-glucanase, and then recovering the enzyme for use as an oral therapeutic agent.

Abstract: An oral therapeutic substance is formed by modifying a plaque-dispersing enzyme to control and reduce the occurrence of dental caries and periodontal diseases. In one embodiment, the modification is performed by introducing a suitable complexing reagent in combination with carrier and plaque-dispersing glucanohydrolase molecules to molecularly alter the glucanohydrolase. The modification, while having insignificant effects on the catalytic activity of the enzyme, will increase the binding capability of the enzyme to substances of which the tooth surface is formed. The activity of the enzyme on the tooth surface will therefore be maintained for longer periods of time to combat plaque build-up.