Simultaneous isolation of the yeast cytosol and well-preserved mitochondria with negligible contamination by vacuolar proteinases.

Disruption of yeast spheroplasts by DEAE-dextran in isoosmotic conditions allows isolation of relatively undamaged subcellular fractions from yeast. The preservation of mitochondria and vacuoles permits the simultaneous isolation of the cytosol with negligible contamination by vacuolar proteinases and therefore, virtually eliminates proteolytic artefacts.