title: The major soluble cytochromes of the obligately aerobic sulfur bacterium, Thiobacillus neapolitanus.
abstract: Four cytochromes were isolated from soluble extracts of the aerobic sulfur bacterium, Thiobacillus neapolitanus. The two most abundant proteins were purified to homogeneity and thoroughly characterized. Cytochrome c-554 (547) is a monomeric, small molecular weight protein which is unusual in having two well-resolved alpha peaks in UV-visible absorption spectra. The redox potential is 208 mV. Native cytochrome c-549 is oligomeric, but has a subunit size of about 26,000. The yield of this protein could be improved dramatically by washing membranes with 30% ammonium sulfate, but the material solubilized by this method had a larger native molecular weight than that in the initial 0.1 M Tris-Cl extract and behaved differently on chromatography. The properties of cytochrome c-549 including subunit size and UV-visible absorption spectra are similar to mitochondrial cytochrome c1 and chloroplast cytochrome f, which suggests that it may be a modified form of the predominant membrane cytochrome. Based on cytochrome content, it is suggested that T. neapolitanus is not closely related to other thiobacilli.
authors.forename: P A
authors.initials: PA
authors.lastname: Trudinger
authors.forename: T E
authors.initials: TE
authors.lastname: Meyer
authors.forename: R G
authors.initials: RG
authors.lastname: Bartsch
authors.forename: M D
authors.initials: MD
authors.lastname: Kamen
mesh_terms: D000596:Amino Acids / Q000032:analysis; D003574:Cytochrome c Group / Q000032:analysis*; D003580:Cytochromes / Q000032:analysis*; D008970:Molecular Weight; D013056:Spectrophotometry, Ultraviolet; D013057:Spectrum Analysis; D013855:Thiobacillus / Q000201:enzymology*
chemical_list: D000596:Amino Acids; D003574:Cytochrome c Group; D003580:Cytochromes; C020267:cytochrome c556