Effect of the alpha-glucosidase inhibitor, acarbose, on disaccharide splitting enzymes in human dental plaque.

Inhibition of microbial enzymes in human dental plaque catalyzing the cleavage of the disaccharides maltose, sucrose and lactose was carried out with the alpha-glucosidase inhibitor, acarbose. The maltases from plaque homogenates were totally inhibited, whereas the inhibition of the invertases varied considerably. With increasing inhibitor concentrations, from 1 mM to 50 mM, the inhibition of the invertases increased. Preincubation for 30 min of the plaque homogenate with inhibitor resulted in a 20% increase of the inhibition of invertase activity. The inhibitor showed non-competitive inhibition of the invertases in the homogenates, whereas the maltases were competitively inhibited. The lactases were not inhibited at all. The invertases from human dental plaque may be alpha-glucosidases and/or beta-fructosidases.