Cytocbromec-554 derived from the blue-green alga Spirulina platensis

Cytochrome c-554 was purified from Spirulina platensis and someof its properties were studied. The cytochrome shows absorptionpeaks at 354, 410 and 529 nm in the oxidized form and at 318,416, 523 and 553.6 nm in the reduced form. The a peak at 553.6nm is slightly asymmetric with a shoulder around 550 nm. Theisoelectric point, midpoint redox potential and molecular weightof the cytochrome are 4.9, +0.35 V and 10,000, respectively.The cytochrome reacts fairly rapidly with Pseudomonas aeruginosanitrite reductase but does not react with cow cytochrome oxidase.The reactivities with the two enzymes of the S. platensis cytochromehave been compared with those of other algal c-type cytochromes. (Received August 22, 1977; )