MadSci Network: Biochemistry

Re: what do we use sucrose density gradient technique for ?

Date: Mon Jan 22 17:53:21 2007
Posted By: Karin Crowhurst, Post-doc/Fellow, Biochemistry
Area of science: Biochemistry
ID: 1169173671.Bc

Hi David,

The technique is generally used for centrifugation of samples (where you spin something at very high speed). Sucrose density gradient centrifugation is one type of density gradient centrifugation, also known as Zonal Centrifugation. Basically, a solution mixture of biochemical molecules (proteins, DNA, etc) is carefully layered on top of a sucrose gradient. During centrifugation, each species of macromolecule in the original solution moves through the gradient at a rate that is mainly dictated by its mass (or size).

As a result, the Zonal Centrifugation technique allows the separation of macromolecules in a mixture. This is a mild, non-denaturing procedure (does not alter the structure or shape of the biological molecules), and is useful for things like protein purification or intact cells. Sucrose is a popular choice for this method because it is a neutral molecule that dissolves in water and does not tend to interact with biological molecules.

Hope this is what you are looking for!

- Karin

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