The Mitochondrial Fractionation Kit is designed to facilitate the study of apoptotic and signal transduction pathways. It provides a unique formulation of buffers and reagents that enable isolation of highly enriched mitochondrial and cytosolic fractions from various mammalian cell lines, including both apoptotic and non-apoptotic cells. The fractionation procedure is simple and easy to perform. No ultracentrifugations are required and no toxic chemicals are involved.