Inorganic pyrophosphatase activity in a plaque calcifying microorganism: Bacterionema matruchotii

The presence and activity of an alcaline pyrophosphatase of Bacterionema matruchotii, a Gram positive filamentous organism present in the bacterial plaque and calculus was studied. A strong enzymatic activity was demonstrated. The optimal conditions for this activity (alcaline pH, magnesium cofactor) have to be related to the pyrophosphatase conditions found in other calcifiable structures. The activity was shown in intact bacteria as well as in the culture medium devoid of micro-organisms. The strongest activity having been demonstrated in broken cells, it can be postulated that the enzyme is active inside the cell. The hypothesis of a contribution of Bacterionema matruchotii to the mineral phase formation is proposed; it is possible that the pyrophosphatase produced by this microorganism contributes to the mineralization process involved in dental calculus formation.