Catalyzes the oxidative decarboxylation of pyruvate to acetyl-CoA and carbon dioxide. The two electrons that are generated as a result of pyruvate decarboxylation are used in the reduction of low potential ferredoxins, which provide reducing equivalents for central metabolism. Also catalyzes the reverse reaction, i.e. the synthesis of pyruvate from acetyl-CoA and carbon dioxide. Appears to function physiologically in both directions (PubMed:10878009). The oxidation of pyruvate by PFOR is required to connect glycolysis and the Wood-Ljungdahl pathway of reductive acetogenesis. The conversion of acetyl-CoA to pyruvate links the Wood-Ljungdahl pathway of autotrophic CO2 fixation to the reductive tricarboxylic acid cycle (PubMed:10878009, PubMed:29581263). Can use methyl viologen as electron carrier in vitro (PubMed:9214293, PubMed:29581263). CoA + 2 oxidized [2Fe-2S]-[ferredoxin] + pyruvate = acetyl-CoA + CO2 + H(+) + 2 reduced [2Fe-2S]-[ferredoxin] Binds 3 [4Fe-4S] clusters per subunit. Binds 1 thiamine pyrophosphate per subunit. Binds 1 Mg(2+) ion per subunit. kcat is 3.2 sec(-1) for the synthesis of pyruvate from acetyl-CoA and CO2 with methyl viologen as electron donor (PubMed:10878009). kcat is 2.0 sec(-1) for the synthesis of pyruvate from acetyl-CoA and CO2 with reduced ferredoxin as electron donor (PubMed:10878009). kcat is 28 sec(-1) for the oxidative decarboxylation of pyruvate with methyl viologen as electron acceptor (PubMed:10878009). kcat is 33 sec(-1) for the oxidative decarboxylation of pyruvate with methyl viologen as electron acceptor (PubMed:29581263). kcat is 29.6 sec(-1) for the oxidative decarboxylation of pyruvate with oxidized ferredoxin as electron acceptor (PubMed:10878009). kcat is 19.8 sec(-1) for the oxidative decarboxylation of pyruvate with oxidized rubredoxin as electron acceptor (PubMed:10878009). Homodimer. Belongs to the pyruvate:ferredoxin/flavodoxin oxidoreductase family.