Emerging family of proline-specific peptidases of Porphyromonas gingivalis: Purification and characterization of serine dipeptidyl peptidase, a structural and functional homologue of mammalian prolyl dipeptidyl peptidase IV

Porphyromonas gingivalis is an asaccharolytic and anaerobic bacterium that possesses a complex proteolytic system which is essential for its growth an d evasion of host defense mechanisms. In this report, we show the purificat ion and characterization of prolyl dipeptidyl peptidase IV (DPPIV) produced by this organism. The enzyme was purified to homogeneity, and its enzymati c activity and biochemical properties were investigated. P. gingivalis DPPI V, like its human counterpart, is able to cleave the N terminus of syntheti c oligopeptides with sequences analogous to those of interleukins 1 beta an d 2. Additionally, this protease hydrolyzes biologically active peptides in cluding substance P, fibrin inhibitory peptide, and beta-casomorphin. South ern blot analysis of genomic DNA isolated from several P. gingivalis strain s reveal that a single copy of the DPPIV gene was present in all strains te sted.