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Sucrose gradient centrifugation Definition
Technique for the characterization and preparation of subcellular particles. A sucrose gradient is used to fill a centrifuge tube of the type swinging-bucket design. The bottom is the most dense, and the top the least dense. The solution is then layered with a suspension of the particles. Centrifugation separates particles in the gradient according their density. The centrifugation is over. After that, the bottom of the tube with sucrose particles of equal density drips into a series receiving tubes.
Sucrose gradient centrifugation, a type density gradient centrifugation, is where sucrose is used to form a density gradient.
Principle of Sucrose gradient centrifugation
Sucrose gradient centrifugation works on the principle of molecules settling down under a centrifugal force until reaching a medium having the same density as theirs. A medium with sucrose gradient, which has either a lower or higher density at its top, is used in this instance. As the sample rotates, the centrifugal force created by the rotation of the sample causes the molecules to move through the medium. As they travel through the density gradient, the more dense molecules move towards the bottom. The molecules are then suspended at the point where the density of the particles equals that of the surrounding medium. This allows molecules of different densities to be separated at different layers, which can then be used for various recovery processes.
Sucrose gradient centrifugation Protocols
- You can create a density gradient of sucrose by placing the lower concentration of sucrose in a centrifuge tube and gently placing the higher concentrations over the lower.
- The sample is then placed on top of the gradient and the tubes are then placed in an ultracentrifuge.
- The particles move through the gradient until their density equals that of the surrounding medium.
- The fractions are separated and removed, which results in the separation of the particles.
Applications of Sucrose gradient centrifugation
- Sucrose gradient centrifugation can be used to separate macromolecules such as DNA andRNA.
- This can also be used to analyze protein complexes, as well as to determine the size and density of other macromolecules.