Mitochondrial iron content

Gear and Bednarek (1972) have recently adapted a Coulter counter technique to the determination of mitochondrial size and number. Large differences in the size of mitochondria from rat liver, heart, and kidney exist. Cytochrome a - - as, iron content, and cytochrome oxidase activity vary when calculated on the basis of protein, but are much more imiform when considered on a per particle basis. 

Cytochrome / can be isolated in a particle of molecular weight 103,000 containing two molecules of be, one of /, nonheme iron, and lipid (299)— in many ways similar to mitochondrial Complex III. This particle cannot be dissociated further without destroying the be and producing aggregation of 34,000 molecular weight monomers of /. Purified cytochrome f apparently exists as an octamer in solution (298). This octamer is the size of the solubilized particles reported earlier by Forti and co-workers (278), but has twice the heme content. 

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