Disease relevance of pfl

• The act gene was identified and an act mutant as well as the pfl mutant was constructed in Streptococcus mutans [1].
• When Streptococcus sanguis was anaerobically starved, a part of the active form of PFL was converted into a reversible inactive form that was tolerant of oxygen [2].
• These findings suggest that the PFL pathway contributes to the acid production from IPS, and may explain partially why the acids in starved dental plaque are mainly acetate and formate [3].

High impact information on pfl

• Nucleotide sequence analysis of the pfl gene revealed a 2.3-kb open reading frame (ORF) preceded by potential ribosome-binding and promoter-like sequences [4].
• These results are in accord with other approaches indicating that S. mutans has other enzymatic activities, including pyruvate formate-lyase and pyruvate dehydrogenase, for pyruvate metabolism [5].
• Pyruvate formate-lyase (PFL) (formate acetyltransferase; EC 2.3.1.54) of oral streptococci is essential for metabolizing sugar into volatile compounds (formate, acetate, and ethanol) [2].
• Galactose-grown cells of these streptococcal strains had higher pyruvate formate-lyase activity than did glucose-grown cells [6].
• Lactate was less than 50% of the total end product of the strictly anaerobic incubation of the galactose-grown cells of S. mutans with excess glucose, and a significant amount of formate, acetate, and ethanol was produced through the catalysis of pyruvate formate-lyase [6].

Chemical compound and disease context of pfl

• Pyruvate formate-lyase (EC 2.3.1.54) from Streptococcus mutans strain JC2 was purified in an anaerobic glove box, giving a single band on disk and sodium dodecyl sulfate electrophoresis [7].
• These results suggest that the increased NADH/NAD+ ratio during sorbitol metabolism through the inactivation of pyruvate formate-lyase by oxygen inhibited glyceraldehyde-phosphate dehydrogenase and then the acid production of S. mutans and the one in dental plaque [8].

Associations of pfl with chemical compounds

• Continuous culture experiments conducted at pH 6.9 under glucose-limited and ammonia-limited conditions revealed that pfl mRNA was decreased by an excess supply of glucose, as well as by a high growth rate [9].
• The metabolism of sorbitol by S. mutans was seriously impaired by the exposure of the cells to oxygen, and the metabolic rate was reduced to less than 1/20 of that found under strictly anaerobic conditions because of the inactivation of pyruvate formate-lyase [6].
• The inhibition of these triose phosphates in cooperation with the reactivating effect of ferredoxin and the fluctuations of both the enzyme and the triose phosphate levels may efficiently regulate the pyruvate formate-lyase activity in S. mutans in vivo [7].
• The levels of lactate dehydrogenase and fructose 1,6-bisphosphate were not significantly different in these cells, but the level of pyruvate formate-lyase was higher in the galactose- or mannitol-grown cells, and that of triose phosphate was lower in the galactose-grown cells [10].
• Under aerobic conditions, the same S. mutans produced exclusively lactate and pyruvate from the IPS because of the inactivation of PFL by oxygen [3].

Other interactions of pfl

• The amount of pfl mRNA in cells was lower at pH 4.5 than pH 6.9, whereas the level of ldh mRNA was higher at pH 4 [9].

References