%0 Journal Article %A Lu, Wei-Ping %A Kelly, D. P. %T Properties and Role of Sulphite: Cytochrome c Oxidoreductase Purified from Thiobacillus versutus (A2) %D 1984 %J Microbiology, %V 130 %N 7 %P 1683-1692 %@ 1465-2080 %R https://doi.org/10.1099/00221287-130-7-1683 %I Microbiology Society, %X Sulphite: cytochrome c oxidoreductase (sulphite dehydrogenase) was purified 2000-fold from Thiobacillus versutus (A2). The enzyme monomer had a molecular weight of 44000 and a pI value of 4·5 α 0·3. Cytochrome c 551 was intimately associated with the enzyme: separation of the two greatly decreased sulphite dehydrogenase activity, which was not restored by remixing them. The enzyme had a pH optimum around pH 8·0, exhibited a K m of 14 µm for sulphite, and was inhibited noncompetitively by phosphate, with a K i value of 12 mm. It was also inhibited by p-hydroxymercuribenzoate and cyanide. Its involvement in the oxidation of thiosulphate in T. versutus is discussed. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-130-7-1683