Activity of enzymes of various subcellular localisation in cytosol obtained after cell organelle precipitation at pH 5.0.

Acidification to pH 5.0 of various organ homogenates prepared in 0.25 M sucrose causes aggregation of cell organelles. Aggregated organelles are removed through standard centrifugation. Cytosol obtained reveals only slight activity of membrane and lysosomal enzymes. The cytosol is useful for evaluation of changes in enzyme distribution in cell.