title: Purification and characterization of ferredoxin-sulfite reductase from turnip (Brassica rapa) leaves and comparison of properties with ferredoxin-sulfite reductase from turnip roots.
abstract: Ferredoxin-sulfite reductase (Fd-SiR) [hydrogen-sulfide: ferredoxin oxidoreductase, EC 1.8.7.1] from turnip leaves (SiR-L) has been purified to homogeneity and its enzymatic properties compared with that from turnip roots (SiR-R). Each enzyme had a molecular mass of 64.5 +/- 0.5 kDa by SDS-PAGE and an isoelectric point of 5.15 +/- 0.05. Although each had a pH optimum around 7.8 with the same effects of inhibitors, SiR-L had higher heat stability at 60 degrees C than SiR-R. Moreover, SiR-R had a lower K(m) and a higher specificity constant (kcat/K(m)) for turnip leaf ferredoxin than SiR-L. The N-terminal amino acid sequence of SiR-L was different from that of SiR-R. The results of amino acid analysis and peptide mapping suggested that SiR-L and SiR-R have different primary structures.
authors.affiliation: Department of Bioresources Chemistry, Faculty of Horticulture, Chiba University, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Takahashi
authors.forename: W C
authors.initials: WC
authors.lastname: Yip
authors.forename: G
authors.initials: G
authors.lastname: Tamura
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D029681:Arabidopsis Proteins; D001937:Brassica / Q000201:enzymology*; D004591:Electrophoresis, Polyacrylamide Gel; D007525:Isoelectric Focusing; D007700:Kinetics; D008969:Molecular Sequence Data; D008970:Molecular Weight; D050862:Oxidoreductases Acting on Sulfur Group Donors / Q000737:chemistry / Q000302:isolation & purification*; D010449:Peptide Mapping; D018515:Plant Leaves / Q000201:enzymology*; D010940:Plant Proteins / Q000032:analysis / Q000302:isolation & purification; D018517:Plant Roots / Q000201:enzymology*; D050889:Sulfite Reductase (Ferredoxin); D013447:Sulfites / Q000378:metabolism
chemical_list: D000596:Amino Acids; D029681:Arabidopsis Proteins; D010940:Plant Proteins; D013447:Sulfites; D050862:Oxidoreductases Acting on Sulfur Group Donors; C488954:SIR protein, Arabidopsis; D050889:Sulfite Reductase (Ferredoxin)