title: Purification and properties of adenylyl sulfate reductase from the phototrophic sulfur bacterium, Thiocapsa roseopersicina.
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: D000249:Adenosine Monophosphate / Q000378:metabolism; D000645:Ammonium Sulfate; D001419:Bacteria / Q000201:enzymology* / Q000254:growth & development / Q000378:metabolism; D002474:Cell-Free System; D011232:Chemical Precipitation; D002852:Chromatography, Ion Exchange; D003470:Culture Media; D003580:Cytochromes / Q000032:analysis / Q000378:metabolism; D004579:Electron Transport; D005292:Ferricyanides / Q000378:metabolism; D005415:Flavins / Q000032:analysis; D006418:Heme / Q000032:analysis; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000032:analysis; D008027:Light; D008970:Molecular Weight; D009711:Nucleotides / Q000378:metabolism; D010088:Oxidoreductases / Q000032:analysis / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism; D013045:Species Specificity; D013053:Spectrophotometry; D013431:Sulfates; D013439:Sulfhydryl Reagents / Q000494:pharmacology; D013440:Sulfides / Q000032:analysis; D013455:Sulfur / Q000378:metabolism; D014461:Ultracentrifugation; D014465:Ultrasonics; D014732:Vibration
chemical_list: D003470:Culture Media; D003580:Cytochromes; D005292:Ferricyanides; D005415:Flavins; D009711:Nucleotides; D013431:Sulfates; D013439:Sulfhydryl Reagents; D013440:Sulfides; D000249:Adenosine Monophosphate; D006418:Heme; D013455:Sulfur; D007501:Iron; D010088:Oxidoreductases; D000645:Ammonium Sulfate