The isolation and some properties of dairy cow liver mitochondria

The problem of the isolation of intact mitochondria from dairy cow liver, which arises from the relative rigidity of this tissue for homogenization, was overcome by prehomogenizing the tissue in an Ultra-Turrax TP 18-10 apparatus, followed by homogenization in a Potter-Elvehjem homogenizer. The mitochondria isolated from such a homogenate displayed, on various substrates, ADP/O ratio and a respiratory control ratio (RCR) comparable with those of rat liver mitochondria. The specific activity of DNP-stimulated ATP-ase of mitochondria isolated from dairy cow liver exhibited about 60% of the activity of mitochondria isolated from rat liver; oligomycin inhibition in the two cases was the same. The transport properties of the inner mitochondrial membrane for phosphate, acetoacetate, D,L-3-hydroxybutyrate, malate, fumarate, succinate and citrate were comparable with those of rat liver mitochondria.