Cloning and characterization of the Entamoeba histolytica pyruvate: ferredoxin oxidoreductase gene

In E~ztumoeba histolytica, the microaerophilic protozoan responsible for human amebiasis. glucose is converted to pyruvate by the classical Embden-Meyerhof pathway [l]. In most anaerobic microorganisms, including E. histolvticu, pyruvate is transformed to acetyl-CoA by the pyruvate: ferredoxin oxidoreductase (PFO); a dimeric or tetrameric protein of 240 kDa [2]. In aerobic organisms the same reaction is catalyzed by the pyruvate dehydrogenase complex, which is a multienzymatic system of approximately 10” kDa [3]. The catalytic mechanisms of PFO and the pyruvate dehydrogenase complex are different [4]. The only property in common to both is the presence of thiamine pyrophosphate (TPP) as the