Cytochrome 553 of the alga Bwmilleriopsis filiformis

摘要

Cytochrome 553 of the alga Bumilleriopsis filiformis Vischcr (Chrysophyceae) was purified to apparent homo¬geneity;disc electrophoresis gave only a single band. Some physical and chemical properties are described. It is an f-type cytochrome for the following reasons:n1. There is the typical location of the a band (at 553 nm).n2. The absorption maximum of the y band is higher than that of the a band (the ratio is 7.5).n3. The standard redox potential is fairly constant between pi 1 6.0 and 8.5. It changes from +340 mV to +309 mV. At pH 7.0 (=Eo') it is +355 mV.n4. CO does not change the spectrum of the reduced form.n5. It has a small molecular weight of only 7,100 (+200). The latter is the smallest ever reported for a cyto¬chrome. It was proved by ultracentrifugation (Archibald method) and SDS disc electrophoresis as well.