Electron Carriers for the Phosphoroclastic Reaction of Desulfovibrio desulfuricans

Desulfovibrio desulfuricans, strain 8303, oxidized pyruvate to acetate, carbon dioxide, and molecular hydrogen. The electron carriers participating in this process are ferredoxin and cytochrome c3. Ferredoxin accepts the electrons from the pyruvic dehydrogenase complex whereas cytochrome c3 does not. However, combining the two carriers, in the clastic system, results in a maximum production of molecular hydrogen and acetyl phosphate. Although both ferredoxin and cytochrome c3 are capable of donating electrons to the hydrogenase of D. sulfuricans, it is believed that a sequential transfer of electrons from the pyruvic dehydrogenase system to the hydrogenase is operating; the sequence is pyruvic dehydrogenase → ferredoxin → cytochrome c3 → hydrogenase.