PMID:1331097

Citation	Anderson, GL, Williams, J and Hille, R (1992) The purification and characterization of arsenite oxidase from Alcaligenes faecalis, a molybdenum-containing hydroxylase. J. Biol. Chem. 267:23674-82
Abstract	The purification and initial characterization of arsenite oxidase from Alcaligenes faecalis are described. The enzyme consists of a monomer of 85 kDa containing one molybdenum, five or six irons, and inorganic sulfide. In the presence of denaturants arsenite oxidase releases a fluorescent material with spectral properties identical to the pterin cofactor released by the hydroxylase class of molybdenum-containing enzymes. Azurin and a c-type cytochrome, both isolated from A. faecalis, each serves as an electron acceptor to arsenite oxidase and may form a periplasmic electron transfer pathway for arsenite detoxification. Full reduction of arsenite oxidase requires 3-4 reducing equivalents, using either arsenite or dithionite as the electron source. Below 20 K, oxidized arsenite oxidase exhibits an EPR signal with g values of 2.03, 2.01, and 2.00, which integrates to approximately 0.4 spins/protein. Since enrichment in 57Fe results in broadening of this EPR signal, the center giving rise to this signal must contain iron. The most plausible candidates are a [4Fe-4S] high potential iron protein center or a [3Fe-4S] center. The EPR signal observed in oxidized arsenite oxidase disappears upon reduction of the protein with either arsenite or dithionite. Concomitantly, a rhombic EPR signal (g = 2.03, 1.89, 1.76) appears which is similar to that of Rieske-type [2Fe-2S] clusters and spin quantifies to one spin/protein.
Links	PubMed
Keywords	Alcaligenes/enzymology; Amino Acid Sequence; Chromatography, Gel; Chromatography, Ion Exchange; Electron Spin Resonance Spectroscopy; Electrophoresis, Polyacrylamide Gel; Iron/analysis; Kinetics; Molecular Sequence Data; Molecular Weight; Molybdenum/analysis; Oxidoreductases/chemistry; Oxidoreductases/isolation & purification; Oxidoreductases/metabolism; Spheroplasts/enzymology; Sulfides/analysis; Thermodynamics
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
ALCFA:AIOA	Contributes to	GO:0050611: arsenate reductase (azurin) activity	ECO:0000314:		F		Figure 4 describes the steady state kinetics of the arsenate reductase activity in the presence of azurin.	complete CACAO 4276

References

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