Thermotoga maritima Phosphofructokinases: Expression and Characterization of Two Unique Enzymes

Abstract

ABSTRACT A pyrophosphate-dependent phosphofructokinase (PP i -PFK) and an ATP-dependent phosphofructokinase (ATP-PFK) from Thermotoga maritima have been cloned and characterized. The PP i -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 effectors (e.g., phosphoenolpyruvate) but was strongly inhibited by PP i 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.