Biochemical and functional properties of a pyruvate formate-lyase (PFL)-activating system in Streptococcus mutans

Shoko Takahashi-Abbe, K. Abe, N. Takahashi

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)


Streptococcus mutans has an oxygen-sensitive enzyme, pyruvate formate-lyase (PFL), which is a key enzyme in anaerobic sugar fermentation. We have shown that S. mutans has an activating system, including a PFL-activating enzyme (PFL-activase) and an electron transport system; the latter transfers an electron from NADPH to PFL-activase, as occurs in Escherichia coli. NADPH was a physiological electron donor for the electron transport system and as little as 0.02 mM NADPH activated over 80% of PFL of S. mutans. The optimum pH of the PFL-activating system was around 6.8, whereas the optimum of the E. coli system is at alkaline pH. In addition, small dialyzable molecules in cell-free extracts participated in keeping PFL active in S. mutans. These results suggest that, in dental plaque under anaerobic conditions where sugar supply is often limited or pH frequently falls below neutrality, S. mutans always keeps PFL active through the activating system.

Original languageEnglish
Pages (from-to)293-297
Number of pages5
JournalOral Microbiology and Immunology
Issue number5
Publication statusPublished - 2003 Oct


  • Activation
  • Inactivation
  • Oxygen sensitive
  • PFL-activase
  • Pyruvate formate-lyase
  • Pyruvate formate-lyase-activating enzyme
  • Pyruvate formate-lyase-activating system
  • Streptococcus mutans


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