title: Ferrous iron production mediated by tetrathionate hydrolase in tetrathionate-, sulfur-, and iron-grown Acidithiobacillus ferrooxidans ATCC 23270 cells.
abstract: When tetrathionate-grown Acidithiobacillus ferrooxidans ATCC 23270 cells were incubated with ferric ions and tetrathionate at pH 3.0, ferrous ions were produced enzymatically. Fe(3+)-reductase, which catalyzes Fe(3+) reduction with tetrathionate, was purified to homogeneity not only from tetrathionate-grown, but also from sulfur- and iron-grown A. ferrooxidans ATCC 23270 cells. The results for apparent molecular weight measured by SDS-PAGE (52.3 kD) and the N-terminal amino acid sequences of the purified enzymes from iron-, sulfur, and tetrathionate-grown cells (AVAVPMDSTG) indicate that Fe(3+)-reductase corresponds to tetrathionate hydrolase. The evidence that tetrathionate-grown A. ferrooxidans ATCC 23270 cells have high iron-oxidizing activity at the early log phase, comparable to that of iron-grown ATCC 23270 cells, is supported by our finding that tetrathionate hydrolase produces Fe(2+) from tetrathionate during growth on tetrathionate. This is the first report on ferric reductase activity associated with tetrathionate hydrolase.
authors.affiliation: Division of Bioscience, Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan. sugio@cc.okayama-u.ac.jp
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Sugio
authors.forename: Taher M
authors.initials: TM
authors.lastname: Taha
authors.forename: Fumiaki
authors.initials: F
authors.lastname: Takeuchi
mesh_terms: D000595:Amino Acid Sequence; D003470:Culture Media; D004591:Electrophoresis, Polyacrylamide Gel; D005296:Ferrous Compounds / Q000378:metabolism*; D006867:Hydrolases / Q000378:metabolism*; D013455:Sulfur / Q000378:metabolism*; D013776:Tetrathionic Acid / Q000378:metabolism*; D013855:Thiobacillus / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism*
chemical_list: D003470:Culture Media; D005296:Ferrous Compounds; D013455:Sulfur; D013776:Tetrathionic Acid; D006867:Hydrolases; C104756:tetrathionate hydrolase