Biochemical Techniques and Instrumentation

4.1.4. Differential Centrifugation

In differential centrifugation, separation is achieved based on the size of the particles. This type of separation is commonly used in simple pelleting and in  obtaining partially-pure preparation of subcellular organelles and macromolecules. The tissues or cells are first disrupted to release their internal contents and this crude mixture is referred as cell homogenate. The large particles sediment faster than the smaller ones during centrifugation and different subcellular fractions are obtained.

Figure

When a cell homogenate is centrifuged at 600g for 10 min, unbroken cells and heavy nuclei pellet settle to the bottom of the tube. The supernatant is further centrifuged at 10,000g for 20 min to pellet subcellular organelles of intermediate velocities such as mitochondria, lysosomes, and microbodies. These partially-purified organelles can be further purified using density gradient separation.