Figure 5-24. Separation of organelles from rat liver by equilibrium density-gradient centrifugation.

Figure 5-24Separation of organelles from rat liver by equilibrium density-gradient centrifugation

For example, the material deposited as a pellet by centrifugation at 15,000 g (see Figure 5-23) can be resuspended and layered on a density gradient composed of layers of increasingly more dense sucrose solutions in a centrifuge tube. Under centrifugation, each organelle migrates to its appropriate equilibrium density and remains there. To obtain a good separation of lysosomes from mitochondria, the liver is perfused with a solution containing a small amount of detergent before the tissue is disrupted. The detergent is taken into the cells by endocytosis and transferred to the lysosomes, making them less dense than they would normally be, thereby affording a “clean” separation from the mitochondria.

From: Section 5.2, Purification of Cells and Their Parts

Cover of Molecular Cell Biology
Molecular Cell Biology. 4th edition.
Lodish H, Berk A, Zipursky SL, et al.
New York: W. H. Freeman; 2000.
Copyright © 2000, W. H. Freeman and Company.

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