Purification and characterization of ferredoxin from Desulfovibrio vulgaris Miyazaki.
Two ferredoxins, Fd I and Fd II, were isolated and purified from Desulfovibrio vulgaris Miyazaki. The major component, Fd I, is an iron-sulfur protein of Mr 12,000, composed of two identical subunits. The absorption spectra of Fd I and Fd II have a broad absorption shoulder near 400 nm characteristic of iron-sulfur proteins. The purity index, A400/A280, of Fd I is 0.69, and its millimolar absorption coefficient at 400 nm is 3.73 per Fe. It contains two redox centers with discrete redox behaviors. The amino acid composition and the N-terminal sequence of Fd I are similar to those of Fd III of Desulfovibrio africanus Benghazi and Fd II of Desulfovibrio desulfuricans Norway. Fd I does not serve as an electron carrier for the hydrogenase of D. vulgaris Miyazaki, but it serves as a carrier for pyruvate dehydrogenase of this bacterium. The evolution of H2 from pyruvate was observed by a reconstructed system containing purified hydrogenase, cytochrome C3, Fd I, partially purified pyruvate dehydrogenase, and CoA. The H2-sulfite reducing system can be reconstructed from the purified hydrogenase, cytochrome C3, Fd I and desulfoviridin (sulfite reductase), but the reaction rate is very slow compared to that of the crude extract at the same molar ratio of the components.
Ogata
M
M
Department of Chemistry, Shizuoka University.
Kondo
S
S
Okawara
N
N
Yagi
T
T
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D003901:Desulfovibrio / Q000378:metabolism*; D005288:Ferredoxins / Q000302:isolation & purification / Q000378:metabolism*; D007700:Kinetics; D046911:Macromolecular Substances; D008970:Molecular Weight; D010084:Oxidation-Reduction
D000596:Amino Acids; D005288:Ferredoxins; D046911:Macromolecular Substances