Spectrophotometric Properties and Enzymatic Activity of Purified Cytochrome Oxidase

Spectrophotometric Properties and Enzymatic Activity of Purified Cytochrome Oxidase 

Cytochrome oxidase purified from N. crassa mitochondria displayed absorption maxima at 602 nm, 427 nm, and 279 nm in the air-oxidized form and at 604 nm and 442 nm in the dithionite-reduced form (Fig. 5). The ratio of the absorbance of the protein at 278 nm to the aborbance of the heme at 428 nm is 2.5. Specific heme contents in the range 10-15 / mol/g protein were found the exact values depended on the methods used for heme and protein determination.The purified cytochrome oxidase was enzymatically active turnover rates of 2-5 mol ferrocytochrome c oxidized per mmol cytochrome aa per min were measured with purified cytochrome oxidase and rates of 5-8 mol were measured with whole mitochondrial membranes tested under the same conditions. With regard to these properties, the cytochrome oxidase preparation from N. crassa closely resembled cytochrome oxidase preparations from beef heart, yeast,and L. migratoria.  

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