Purification and properties of cytochrome b556 in the respiratory chain of aerobically grown Escherichia coli K12.
Cytochrome b556, a major component of type b cytochromes in the respiratory chain of aerobically grown Escherichia coli, was purified to near homogeneity. It was solubilized from cytoplasmic membranes by treatment with Sarkosyl/cholate mixture and purified by gel filtration on Sephadex G-200. The purified cytochrome b556 is an oligomer composed of identical polypeptides, with a molecular weight of 17,500, determined by gel electrophoresis in the presence of sodium dodecyl sulfate. It contains equimolar amounts of heme and polypeptide but no detectable non-heme iron, phospholipid, or dehydrogenase. Its isoelectric point was determined to be 8. 5. The cytochrome b556 is highly hydrophobic in its amino acid composition and does not contain any half-cystine residues. The purified cytochrome b556 is spectrophotometrically pure and the alpha absorption peak in its difference spectrum at 77 K is at 556 nm. The molar extinction coefficient of cytochrome b556 was determined as 22.8 cm-1 mM-1. Its oxidation-reduction potential was found to be -45 mV. It could be reduced by D-lactate dehydrogenase of E. coli in the presence of menadione.[1]References
- Purification and properties of cytochrome b556 in the respiratory chain of aerobically grown Escherichia coli K12. Kita, K., Yamato, I., Anraku, Y. J. Biol. Chem. (1978) [Pubmed]
Annotations and hyperlinks in this abstract are from individual authors of WikiGenes or automatically generated by the WikiGenes Data Mining Engine. The abstract is from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.About WikiGenesOpen Access LicencePrivacy PolicyTerms of Useapsburg
