AN f-TYPE CYTOCHROME FROM CHLORELLA VULGARIS

概要

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A method for isolating an f-type cytochrome (Chlorella cytochrome 554) from Chlorella vulgaris var. viridis (CHODAT) utilizing N, N-diethylaminoethylcellulose is described. The spectrum of reduced Chlorella cyt. 554 has absorption maxima at 554mμ (α-band), 524mμ (β-band), 417mμ (SORET band), 352mμ, 319mμ and 275mμ (protein band). The oxidized form has absorption maxima at 554mμ, 530mμ (β-band), 412mμ (SORET band), 360mμ, 322mμ and 275μ (protein band). The spectral characteristics resembled other f-type cytochromes, e. g. in the high SORET to α-extinction ratio (6.8) and an asymmetric α-absorption band (especially at liquid N_2 temperature); but characteristic differences were present. Mitochondriafrom white lupine seedlings and sweet potato roots reduced Chlorella cyt. 554. From the effects of antimycin A and 2-heptyl-4-hydroxyquinoline N-oxide it appears that Chlorella cyt. 554 was reduced sequentially before cytochrome a+a3 and near the level of the cytochromes of the b type. Oxidation was slow using lupine mitochondria and nil with sweet potato mitochondria. The oxidation-reduction potential at pH 7.2 and 30° was 0.35V. Ascorbate, cysteine, glutathione and Na_2S_2O_4 readily reduced Chlorella cyt. 554. The cytochrome was not autoxidizable and was slowly oxidized by excess potas-sium ferricyanide. The reduced form did not react with CO and was not adsorbed by IRC-50 or Cellex-P cation exchangers.
日本植物生理学会の論文