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 and evasion of host defense mechanisms. In this report, we show the purification and characterization of prolyl dipeptidyl peptidase IV (DPPIV) produced by this organism. The enzyme was purified to homogeneity, and its enzymatic activity and biochemical properties were investigated. P. gingivalis DPPIV, like its human counterpart, is able to cleave the N terminus of synthetic oligopeptides with sequences analogous to those of interleukins 1β and 2. Additionally, this protease hydrolyzes biologically active peptides including substance P, fibrin inhibitory peptide, and β-casomorphin. Southern blot analysis of genomic DNA isolated from several P. gingivalis strains reveal that a single copy of the DPPIV gene was present in all strains tested.

牙龈卟啉单胞菌（Porphyromonas gingivalis）是一种非发酵性厌氧细菌，其拥有一套复杂的蛋白水解系统，该系统对其生长以及逃逸宿主防御机制至关重要。本研究中，我们对该菌产生的脯氨酰二肽肽酶IV（prolyl dipeptidyl peptidase IV，DPPIV）进行了纯化与表征。该酶已被纯化至均一状态，并对其酶学活性与生化特性进行了研究。牙龈卟啉单胞菌的DPPIV与人类同源酶类似，能够切割序列与白细胞介素1β、2相似的合成寡肽的N端。此外，该蛋白酶还可水解包括P物质、纤维蛋白抑制肽以及β-酪啡肽在内的多种生物活性肽。对从多株牙龈卟啉单胞菌中提取的基因组DNA进行Southern印迹（Southern blot）分析结果显示，在所检测的所有菌株中均仅存在单拷贝的DPPIV基因。