The α Subunit of Toluene Dioxygenase from Pseudomonas putida F1 Can Accept Electrons from Reduced FerredoxinTOL but Is Catalytically Inactive in the Absence of the β Subunit

The oxygenase component of toluene dioxygenase from Pseudomonas putida F1 is an iron-sulfur protein (ISP_TOL) consisting of α (TodC1) and β (TodC2) subunits. Purified TodC1 gave absorbance and electron paramagnetic resonance spectra identical to those given by purified ISP_TOL. TodC1 was reduced by NADH and catalytic amounts of Reductase_TOL and Ferredoxin_TOL. Reduced TodC1 did not oxidize toluene, and catalysis was strictly dependent on the presence of purified TodC2.