Pyruvateferredoxin

Pyruvateferredoxin, typically referred to in biochemistry as the ferredoxin-dependent pyruvate oxidation system, denotes the enzymatic activity that converts pyruvate to acetyl-CoA with the concomitant reduction of ferredoxin. The principal enzyme in this system is pyruvate:ferredoxin oxidoreductase (PFOR; EC 1.2.7.1). PFOR catalyzes the oxidative decarboxylation of pyruvate to acetyl-CoA and CO2, transferring electrons from the substrate to ferredoxin and thereby reducing it.

The overall reaction can be summarized as pyruvate + CoA + ferredoxin_oxidized → acetyl-CoA + CO2 + ferredoxin_reduced. This reaction links glycolysis with acetyl-CoA–based metabolism under anaerobic conditions, providing a carbon skeleton for biosynthesis and reducing equivalents for energy conversion.

Biochemical properties: PFOR is typically a thiamine pyrophosphate (TPP)–dependent enzyme that contains iron-sulfur clusters for electron transfer to ferredoxin. Many PFORs are multimeric and require additional cofactors for proper assembly. The ferredoxin partner carries electrons to other anaerobic pathways, such as hydrogenases (for H2 production) or CODH/ACS systems that convert reduced ferredoxin and CoA into acetate and ATP.

Distribution and role: Ferredoxin-dependent pyruvate oxidation is widespread among strictly anaerobic bacteria and archaea, including Clostridium species and various methanogens. In these organisms, the PFOR–ferredoxin system enables energy conservation in the absence of NAD+-dependent dehydrogenases and supports fermentation and autotrophic pathways.

Significance: Understanding pyruvateferredoxin chemistry informs studies of anaerobic metabolism, dark fermentation, and biotechnological approaches to hydrogen production and renewable acetyl-CoA–derived products.