Molecular Biology Lab Guide

WAYS TO SEPARATE DNA FROM OTHER CELLULAR MATERIALS: BINDING AND WASHING

Written by MicroDok

 

  1. Organic Extraction

When phenol or a mixture of phenol:chloroform is mixed with a  cell Lysate, two phases form: an aqueous and an organic phase. The polar DNA partitions into the polar or “aqueous phase”, and denatured proteins and other cellular debris partition into the organic phase.

 

  1. Salting Out

Salts are thought to dehydrate proteins, causing them to become less hydrophilic and are subsequently denatured. The denatured proteins lose solubility and precipitate; precipitated proteins and cellular debris are removed by centrifugation. Salts typically used in these protocols include sodium, potassium acetate or ammonium.

 

  1. Bind to Solid Support

Most modern DNA purification methods are based on purification of DNA from crude lysates by selective binding to a support material. These support materials include silica-based supports and anion-exchange resins. Generally these methods are quicker and more convenient than other methods because they do not require any organic solvents and can be miniaturized and automated for high throughput.

 

Source: PROMEGA

www.promega.com

 

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