Proteomics/Protein Separations - Centrifugation/Preparative Centrifugation vs. Analytical Centrifugation

Table of Contents: Protein Separations - Centrifugation

1. History of the Centrifuge
2. How the Centrifuge Works
3. Density Gradient Centrifugation
4. Differential Centrifugation
5. Preparative Centrifugation vs. Analytical Centrifugation

Two types of ultracentrifuges developed: analytical and preparative

Analytical

· Uses small sample size (less than 1 ml)

· Built in optical system to analyze progress of molecules during centrifugation

· Uses relatively pure sample

· Used to precisely determine sedimentation coefficient and MW of molecules

· Beckman Model E is an example of centrifuge used for these purposes.

Preparative

· Larger sample size can be used

· No optical read-out – collect fractions and analyze them after the run

· Less pure sample can be used

· Can be used to estimate sedimentation coefficient and MW

· Generally used to separate organelles and molecules. Most centrifugation work done using preparative ultracentrifuge

· Several models available, including L5-65 and L5-75 used for preparative purposes.