Studies on a ferrous-ion-oxidizing bacterium. II. Cytochrome composition

Purification and characterization of two new c-type cytochromes involved in Fe2+ oxidation from Thiobacillus ferrooxidans

“…Partial release of this cytochrome after chloroform treatment and osmotic shock and the necessity of using detergent for its purification support the suggestion that this cytochrome is a peripheral protein associated with the cytoplasmic membrane as is the case in other bacteria [26]. Additional evidence for the location of this cytochrome is that the periplasmic pH of this bacterium has been reported to be 2.0 [3], and this cytochrome is very stable at acidic pH. This 21-kDa cytochrome c was oxidized by the membrane fraction of T. ferrooxidans.…”

“…As the change in free energy liberated by electron transport from Fe 2÷ to 0 2 is small, it has been suggested that the bacterium may have an unusual respiratory chain [2]. For example, the c-type cytochrome content of T. ferrooxidans is very high; up to 10% of total cellular protein [3]. Furthermore, potentiometric and kinetic studies have indicated that at least two c-type cytochromes and one cytochrome c l are present in the respiratory chain [4].…”

The role of Thiobacillus ferrooxidans in hydrometallurgical processes

“…The isolation of cytochrome c and cytochrome a from T. ferrooxidans [ 104] allowed the postulation of iron oxidation through the cytochrome system with oxygen as the final electron acceptor [96,[104][105][106]:…”

Molecular aspects of the electron transfer system which participates in the oxidation of ferrous ion by Thiobacillus ferrooxidans

“…Cytochromes a and c were reduced by the addition of Fe 2+. Vernon et al [12] reported that cytochromes a I and c were present in a ferrous-ion-oxidizing bacterium (probably T. ferrooxidans). They partially purified cytochrome c-552 from the organism and determined its Era,7.…”