Open AccessAcid‐stable cytochromes in ferrous ion oxidizing cell‐free preparations from Thiobacillus ferrooxidans
Author(s) -
Mansch R.,
Sand W.
Publication year - 1992
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1992.tb05239.x
Subject(s) - ferrous , oxidizing agent , chemistry , sulfur , cytochrome , thiobacillus , cytochrome c , inorganic chemistry , membrane , enzyme , biochemistry , organic chemistry , mitochondrion
Cell‐free preparations from ferrous ion‐ and sulfur‐grown Thiobacillus ferrooxidans prepared under neutral (pH 7.5) or acidic conditions (pH 2.0) were compared. Under neutral conditions the ferrous ion‐oxidizing system of T. ferrooxidans was membrane‐bound. At acidic conditions, the enzyme system became partially solubilized. In ferrous ion‐oxidizing membranes of ferrous ion‐grown cells (neutral conditions) a 1 ‐, c‐ and b‐type cytochromes were present. The acidic preparations contained only cytochrome a 1 and c. At least three acid‐stable c‐type cytochromes (M r 60 000, 30 000 and 25 000), an acid‐stable protein with non‐convalently bound heme group (M r probably rusticyanin, were detected in ferrous ion oxidizing preparations. Membranes of sulfur‐grown cells prepared under neutral conditions still oxidized ferrous ions, and contained a 1 ‐, b‐, c‐ and in addition an aa 3 ‐type cytochrome. Cytochrome b and aa 3 were acid‐labile.