CYTOCHROMES OF BACILLUS SUBTILIS .3. PHYSICOCHEMICAL AND ENZYMATIC PROPERTIES OF CYTOCHROMES C-550 AND C-554

Physicochemical and enzymatic properties were determined with highly purified preparations of cytochromes c-550 and c-554 derived from Bacillus subtilis K.Cytochrome c-550 possessed isoelectric point at pH8.65 at 2°C and Eo'** of 0.21 volt at pH7.0 and 21°C. Molecular weight was determined to be 12,500 by gel filtration method and 13,000 on the basis of heme c content. Cytochrome c-550 scarcely reacted with bovine and yeast cytochromes a, but it reacted rapidly with Pseudomonas cytochrome oxidase [EC 1. 9. 3. 2] and Bacillus ETP**. It was reduced with NADH in the presence of ETP.Cytochrome c-554 possessed one molecule of heme c in one molecule, although its α-peak at 554 mμ was asymmetric, accompanied by a bump at 550 mμ. Isoelectric point and Eo' of the cytochrome were determined to be at pH4.44 and 2°C and -0.08 volt at pH7.0 and 21°C, respectively. Molecular weight of cytochrome c-554 was determined to be 14,000 by gel filtration and amino acid analysis. Cytochrome c-554 reacted rapidly with Pseudomanas cytochrome oxidase, but scarcely reacted with bovine cytochrome α.Both the hemoproteins were contained in the ETP and their function as an electron carrier was also investigated. © 1969 BY THE JOURNAL OF BIOCHEMISTRY.