Cytochromes of a Blue-Green Alga: Extraction of a c-Type with a Strongly Negative Redox Potential

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Science  11 Oct 1963:
Vol. 142, Issue 3589, pp. 234-235
DOI: 10.1126/science.142.3589.234


Aqueous extraction of lyophilized Anacystis nidulans cells followed by chromatography on diethylaminoethyl cellulose separates three different c-type cytochromes. Of the two present in highest concentration, cytochrome-554 has a + 0.35-volt redox potential and resembles the cytochrome f of other photosynthetic tissues, while cytochrome-549 has a -0.26-volt potential. The possible participatidn of cytochrome-549 in electron transport in photosynthesis in this alga at a more negative oxidation-reduction potential than previously postulated for any cytochrome is inferred from the similarities in its spectra to the light-induced spectral changes in vivo observed by others.