Purification and Properties of Cytochrome c-553 and Cytochrome B-560 from Tetrahymena pyriformis

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Cytochrome c-553 and cytochrome B-560 were highly purified from the protozoan, Tetrahymena pyriformis. Cytochrome c (553, T. pyriformis) possesses an absorption maximum at 410 mμ in the oxidized form, and maxima at 414, 523 and 553mμ in the reduced form. The ratio of A_{414 mμ}(reduced)/A_553mμ, (reduced) of the cytochrome is 5.35, and the mil-limolar extinction coefficient of the a-peak is 27.4. The midpoint redox potential of the cytochrome is about -1-0.25 volt at pH 7.0. The cyto-chrome c is an acidic protein on the basis of its affinity for diethyl-aminoethylcellulose and is not precipitated by saturation with am-monium sulphate. It reacted slowly with Pseudomonas cytochrome oxidase [EC 1. 9. 3. 2], but did not react with cow cytochrome oxidase [EC 1. 9. 3. 1].
Cytochrome B (560, T. pyriformis) shows an absorption peak at 411 mu in the oxidized form, and peaks at 424, 529 and 560mμ in the reduced form. This cytochrome is autoxidizable, and combines with carbon monoxide and cyanide, but not with azide, and does not show any peroxidase activity.