Reduction of fully oxidized Clostridium pasteurianum 8-Feox.,ox. ferredoxin by using pulse-radiolysis techniques yields the half-reduced species 8-Feox.,red. ferredoxin. The subsequent oxidation of 8-Feox.,red. ferredoxin with Co(NH3)5Cl2+ was studied. From a comparison with stopped-flow studies on the 2:1 Co(NH3)5Cl2+ oxidation of 8-Fered.,red. ferredoxin to the 8-Feox.,ox. form it is conclude...

Two ferredoxins have been purified from N2-fixing Mycobacterium flavum. Ferredoxin I had a minimum molecular weight (by amino acid analysis) of 11 230 and contained 7.4 mol Fe and 7.0 mol S2per mol. The ratio of the absorbance at 400 nm to that at 275 nm was 0.7. Ferredoxin I1 had a minimum molecular weight of 13478 and contained 3.4 mol Fe and 3.2 mol S2per mol. The ratio of the absorbance at ...

In an earlier investigation (Shanmugam, K. T., Buchanan, B. B., and Arnon, D. I. (1972) Biochim. Biophys. Acta 256, 477-486) the extraction of ferredoxin from Rhodospirillum rubrum cells with the aid of a detergent (Triton X-100) and acetone revealed the existence of two types of ferredoxin (I and II) and led to the conclusion that both are membrane-bound. In the present investigation, ferredox...

The process of ferredoxin reduction by photosystem I has been extensively investigated by flash-absorption spectroscopy in psaD and psaE deleted mutants from Synechocystis sp. PCC 6803. In both mutants, the dissociation constant for the photosystem I/ferredoxin complex at pH 8 is considerably increased as compared to the wild type: approximately 25- and 100-fold increases are found for PsaD-les...

A covalent stoichiometric complex between photosystem I (PSI) and ferredoxin from the cyanobacterium Synechocystis sp. PCC 6803 was generated by chemical cross-linking. The photoreduction of ferredoxin, studied by laser flash absorption spectroscopy between 460 and 600 nm, is a fast process in 60% of the covalent complexes, which exhibit spectral and kinetic properties very similar to those obs...

The unicellular red alga, Cyanidium cddurium, synthesizes phycocyanobilin from protoheme via biliverdin IXa. In vitro transformation of protoheme to biliverdin IXa and biliverdin IXa to phycobilins were previously shown to require NADPH, ferredoxin, and ferredoxin-NADP+ reductase, as well as specific heme oxygenase and phycobilin formation enzymes. The role of NADPH in these reactions was inves...

The present study was undertaken to obtain information on the involvement of cytochrome P-450 in the 26-hydroxylation on bile acid intermediates and in the 25-hydroxylation of vitamin D3 in human liver mitochondria. Cytochrome P-450 was solubilized from human liver mitochondria and purified two times to a specific content of 0.125 nmol per mg protein. Furthermore, a ferredoxin was isolated from...

The ferredoxin-thioredoxin reductase variable subunit gene of Anacystis nidulans was cloned, and its nucleotide sequence was determined. A single-copy 219-bp open reading frame encoded a protein of 73 amino acid residues, with a calculated Mr of 8,400. The monocistronic transcripts were represented in a 400-base and a less abundant 300-base mRNA form.

Cell extracts of uric acid-grown Clostridium acidurici catalyzed the coupled reduction of NAD(+) and ferredoxin with formate at a specific activity of 1.3 U/mg. The enzyme complex catalyzing the electron-bifurcating reaction was purified 130-fold and found to be composed of four subunits encoded by the gene cluster hylCBA-fdhF2.