Effective method for discriminating between oral bacterial and human alkaline phosphatase activity.

Alkaline phosphatase (ALPase) activity was quantitatively compared in various kinds of oral bacteria. High ALPase activity was detected in 3 species of periodontal bacteria, Porphyromonas gingivalis, Prevotella intermedia and Capnocytophaga sputigena. The ALPase activity detected in these bacteria was almost completely inhibited in the presence of 1% sodium dodecyl sulfate (SDS). By contrast, the activity of mammalian ALPase isoenzymes was not inhibited at all even in the presence of 1% SDS. These results indicate that the ALPase assay in combination with 1% SDS can identify the origin of ALPase detected in gingival crevicular fluid as being from bacteria or from a host response. Clinical examination with adult periodontitis revealed that ALPase activity in gingival crevicular fluid from the patients consisted of a combination of SDS-sensitive and SDS-resistant activities. These findings indicate that ALPase activity detected in gingival crevicular fluid originates not only from bacteria but also from a host response.