Porphyromonas endodontalisが産生する新規のアスパラギン酸特異的ジペプチジルペプチダーゼの解析

概要

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Porphyromonas endodontalis, a black-pigmented anaerobe, is a predominant pathogen of human periapical periodontitis. In contrast to P. gingivalis, a major pathogen of chronic periodontitis, the pathogenic factor(s) of P. endodontalis has been poorly characterized. In this study, the protease activities in the P. endodontalis extracellular fraction were examined using various MCA polypeptides. The results indicated that the extracellular fraction had a spectrum of proteolytic activities distinct from that of P. gingivalis, and that Ala- and Asp-specific proteolytic activities were substantially present in the extracellular fraction. Then, the extracellular fraction was subjected to ion-exchange chromatography. The Asp-specific proteolytic activity was eluted from a DEAE-Sephacel column separately from the Ala-specific one, and the fraction was designated as the DEAE-purified fraction. The further experiments on the effects of protease inhibitors also suggested that the DEAE-purified fraction contains a novel Asp-specific dipeptidylpeptidase. It was confirmed by the MALDI-TOF MS analyses on the substrate preference using neuromedin B and a series of synthetic neuromedin B analogues. Taken together, P. endodontalis possesses a novel Asp-specific dipeptidylpeptidase in the extracellular fraction, which could be involved in an important etiologic process in the specific pathological potential of this organisms in human periapical periodontitis.
2008-12-19