title: Isolation of a soluble and membrane-associated Fe(III) reductase from the thermophile, Thermus scotoductus (SA-01).
abstract: The Fe(III) reductase activity was studied in the South African Fe(III)-reducing bacterium, Thermus scotoductus (SA-01). Fractionation studies revealed that the membrane as well as the soluble fraction contained NAD(P)H-dependent Fe(III) reductase activity. The membrane-associated enzyme was solubilized by KCl treatment and purified to electrophoretic homogeneity by hydrophobic interaction chromatography. A combination of ion-exchange and gel filtration chromatography was used to purify the soluble enzyme to apparent homogeneity. The molecular mass of the membrane-associated Fe(III) reductase was estimated to be 49 kDa, whereas the soluble Fe(III) reductase had an apparent molecular mass of 37 kDa. Optimum activity for the membrane-associated enzyme was observed at around 75 degrees C, whereas the soluble enzyme exhibited a temperature optimum at 60 degrees C.
authors.affiliation: Department of Microbial, Biochemical and Food biotechnology, Faculty of Natural and Agricultural Sciences, University of the Free State, Bloemfontein, South Africa.
authors.forename: Christelle
authors.initials: C
authors.lastname: Möller
authors.forename: Esta
authors.initials: E
authors.lastname: van Heerden
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D002462:Cell Membrane / Q000201:enzymology; D038181:FMN Reductase / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D006358:Hot Temperature; D007501:Iron / Q000378:metabolism; D007700:Kinetics; D008565:Membrane Proteins / Q000737:chemistry / Q000302:isolation & purification*; D013824:Thermus / Q000201:enzymology*
chemical_list: D001426:Bacterial Proteins; D008565:Membrane Proteins; D007501:Iron; D038181:FMN Reductase; C023903:ferric citrate iron reductase