Coupling of the pathway of sulphur oxidation to dioxygen reduction: characterization of a novel membrane-bound thiosulphate:quinone oxidoreductase
作者:Fabian H. Müller、Tiago M. Bandeiras、Tim Urich、Miguel Teixeira、Cláudio M. Gomes、Arnulf Kletzin
DOI:10.1111/j.1365-2958.2004.04193.x
日期:——
DQ it was 397 mU (mg protein)(-1) at 80 degrees C. The Km values were 2.6 mM for thiosulphate (k(cat) = 167 s(-1)), 3.4 mM for ferricyanide and 5.87 micro M for DQ. The enzymic activity was inhibited by sulphite (Ki = 5 micro M), metabisulphite, dithionite and TritonX-100, but not by sulphate or tetrathionate. A mixture of caldariella quinone, sulfolobus quinone and menaquinone was non-covalently bound
硫代硫酸盐是嗜热古生古细菌Acidianus ambivalens中元素硫氧化途径初始步骤的产物之一。在该生物的需氧生长细胞的膜提取物中发现了一种新的硫代硫酸盐:醌氧化还原酶(TQO)活性。从溶解的膜级分中纯化酶21倍。TQO氧化了硫代硫酸盐,产物为四硫代酸盐,铁氰化物或癸基泛醌(DQ)为电子受体。铁氰化物的最大比活在92摄氏度和pH 6下为73.4 U(mg蛋白质)(-1),DQ在80摄氏度下为397 mU(mg蛋白质)(-1)。Km值为2.6 mM对于硫代硫酸盐(k(cat)= 167 s(-1)),对于铁氰化物为3.4 mM,对于DQ为5.87 micro M. 亚硫酸盐(Ki = 5 micro M),偏亚硫酸氢盐,连二亚硫酸盐和TritonX-100,但不被硫酸盐或四硫代硫酸盐。Caldariella quinone,sulfolobus quinone和menaquinone的