acetyl-CoA + formate = CoA + pyruvate Fermentation; pyruvate fermentation; formate from pyruvate: step 1/1. Homodimer. By pfl-activating enzyme under anaerobic conditions by generation of an organic free radical. Exposure of activated pfl to oxygen resulted in cleavage at the glycine residue harboring its organic radical with loss of the 25 C-terminal AA. Several mechanisms have been proposed based on complexes formed with substrate analogs. After activation by the glycine radical, the cysteine radical, Cys-420, can abstract hydrogen atoms from the other active site cysteine, Cys-419, and from coenzyme A, and it can also transfer hydrogen atoms to product radicals. The other active site cysteine can attack the central carbonyl of pyruvate and covalently bind the product acetyl group. Belongs to the glycyl radical enzyme (GRE) family. PFL subfamily.