Involved in the anaerobic metabolism of phenylalanine and phenylacetate. Catalyzes the oxidative decarboxylation of phenylglyoxylate to benzoyl-CoA and CO(2). It can also react slowly with 2-oxo-3-methylbutanoate and use different electron acceptors such as benzyl viologen, methyl viologen, FAD or FMN, but NAD seems to be the physiological electron acceptor. Also catalyzes an isotope exchange between CO(2) and the carboxyl group which proves partial or complete reversibility of the oxidative decarboxylation reaction. CoA + NAD(+) + phenylglyoxylate = benzoyl-CoA + CO2 + NADH Binds 3 [4Fe-4S] clusters per heteropentamers. Activated by magnesium ions and thiamine diphosphate. Optimum pH is 8 when measured with benzyl viologen. Half-maximal activities are obtained at pH 9 and pH 6.8. Dimer of heteropentamers composed of an alpha (PadG), a beta (PadI), a gamma (PadE), a delta (PadF) and an epsilon (PadH) subunit. Induced anaerobically by phenylalanine, phenylacetate or phenylglyoxylate.