Cytochrome f from spinach and cyanobacteria. Purification and characterization.
Cytochrome f has been purified from spinach chloroplasts and from the photosynthetic membranes of the cyanobacterium Spirulina maxima. The spinach protein has an isoelectric point of 5.2 and gives a single band on isoelectric focusing gels. The S. maxima cytochrome shows a major band with a pI of 4.01 and a minor band with a pI of 3.97. S. maxima cytochrome f has a molecular weight approximately 38,000 and is monomeric, while the spinach protein is slightly smaller, approximately 36,000 daltons, and aggregates to form an octamer. S. maxima cytochrome f has an E'0 of +339 mV which is close to that of cytochromes f from higher plants. The NH2-terminal amino acid sequences of the cytochromes show striking similarities. Spinach cytochrome f shows a clear preference for oxidation by spinach plastocyanin and S. maxima cytochrome f is more readily oxidized by its in vivo reaction partner, cytochrome c553.
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000458:Cyanobacteria / Q000378:metabolism*; D003580:Cytochromes / Q000302:isolation & purification* / Q000378:metabolism; D045348:Cytochromes f; D046911:Macromolecular Substances; D008970:Molecular Weight; D010084:Oxidation-Reduction; D010944:Plants / Q000378:metabolism*; D010970:Plastocyanin / Q000378:metabolism; D013045:Species Specificity; D013053:Spectrophotometry
D000596:Amino Acids; D003580:Cytochromes; D046911:Macromolecular Substances; D010970:Plastocyanin; D045348:Cytochromes f