Study of quinol peroxidase of aggressive periodontopathic bacterium as a virulence factor

2016 Fiscal Year Final Research Report

• Project/Area Number: 25462877
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Morphological basic dentistry
• Research Institution: The Nippon Dental University
• Principal Investigator: Konishi Kiyoshi 日本歯科大学, 生命歯学部, 教授 (20178289)
• Project Period (FY): 2013-04-01 – 2017-03-31
• Keywords: ペルオキシダーゼ / キノン / 呼吸鎖 / 侵襲性歯周炎

Outline of Final Research Achievements

Oral pathogen for aggressive periodontitis encodes quinol peroxidase (QPO). Irreversible inactivation of QPO by high concentration of H2O2 exhibited pseudo-first order kinetics. Analyses of initial-rate kinetics and product inhibition of QPO indicate that enzyme catalytic mechanism is explained by a Ping Pong Bi Bi system. In addition, one of the three heme c moieties of QPO is maintained in an oxidized form even at increased ratios of [Q1H2]/[Q1], suggesting that QPO is reduced in the absence of H2O2 and only two of the three heme c moieties are reduced in the presence of high concentration of the Q1H2. We also found that ascochlorin (competitive-type, Ki=24.7 nM), ilicicolin B (mixed-type, Ki=576 nM), ilicicolin F (competitive-type, Ki=19.5 nM), N-heptyl-quinoline-N-oxide (competitive-type, Ki=1.0 microM), 2-heptyl-3-hydroxy-4-quinolone (noncompetitive-type, Ki=7.0 microM) are potent inhibitor for QPO.

Free Research Field

口腔微生物学