Abstract
Adenylyl sulfate reductase was purified from Thiocapsa roseopersicina 60- to 80- fold, and the properties were studied. The molecular weight is 180,000. The enzyme contains, per molecule; one flavine group, two heme groups of cytochrome c character, four atoms of nonheme iron, and six labile sulfide groups. Cytochrome c and ferricyanide serve as electron acceptors. With ferricyanide as the electron acceptor, the pH optimum of the enzyme is at 8.0; with cytochrome c, the pH optimum is at 9.0. Of the nucleotides studied, adenosine 5'-monophosphate is most effective. The influence of substrate concentrations on the activity of the enzyme was studied, and the K(m) values for sulfite, adenosine 5'-monophosphate, ferricyanide, and cytochrome c were determined. The properties of the enzyme are compared with those of adenylyl sulfate reductases purified from sulfate-reducing bacteria and thiobacilli.
MeSH terms
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Adenosine Monophosphate / metabolism
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Ammonium Sulfate
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Bacteria / enzymology*
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Bacteria / growth & development
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Bacteria / metabolism
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Cell-Free System
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Chemical Precipitation
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Chromatography, Ion Exchange
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Culture Media
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Cytochromes / analysis
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Cytochromes / metabolism
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Electron Transport
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Ferricyanides / metabolism
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Flavins / analysis
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Heme / analysis
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Hot Temperature
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Hydrogen-Ion Concentration
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Iron / analysis
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Light
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Molecular Weight
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Nucleotides / metabolism
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Oxidoreductases* / analysis
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Oxidoreductases* / antagonists & inhibitors
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Oxidoreductases* / isolation & purification
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Oxidoreductases* / metabolism
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Species Specificity
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Spectrophotometry
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Sulfates
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Sulfhydryl Reagents / pharmacology
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Sulfides / analysis
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Sulfur / metabolism
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Ultracentrifugation
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Ultrasonics
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Vibration
Substances
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Culture Media
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Cytochromes
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Ferricyanides
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Flavins
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Nucleotides
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Sulfates
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Sulfhydryl Reagents
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Sulfides
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Adenosine Monophosphate
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Heme
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Sulfur
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Iron
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Oxidoreductases
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Ammonium Sulfate