Thermotoga maritima phosphofructokinases: Expression and characterization of two unique enzymes

A pyrophosphate-dependent phosphofructokinase (PPi-PFK) and an ATP-dependent phosphofructokinase (ATP-PFK) from Thermotoga maritima have been cloned and characterized. The PPi-PFK is unique in that the K-m and V-max values indicate that polyphosphate is the preferred substrate over pyrophosphate; the enzyme in reality Is a polyphosphate-dependent PFK. The ATP-PFK was not significantly affected by common allosteric effecters (e.g., phosphoenolpyruvate) but was strongly inhibited by PPi and polyphosphate. The results suggest that the control of the Embden-Meyerhof pathway in this organism is likely to be modulated by pyrophosphate and/or polyphosphate.