The Protein Man's Blog | A Discussion of Protein Research

DNA Purification: Why Should You Purify Your DNA Samples?

Posted by The Protein Man on Feb 27, 2013 5:00:00 AM
The Protein Man

Question:

What is the purpose of purifying DNA samples?

The Protein Man Says:

DNA purification is considered to be of vital importance for most methods involved in molecular biology, genomics, biotechnology and clinical research since it can help determine the success or failure of all your immediate and downstream experimentations. In a nutshell, DNA purification can help you:

  • Extract ample amounts of your genomic and/or plasmid DNA sample from a limited source to satisfy the requirements of your research.

  • Purify it to reduce the amount of contaminants that can compromise the results of your research and shorten the shelf-life of your precious samples.

dna purification, molecular biologyThink of it this way. When you start with a contaminated DNA sample, there is a high probability that you will get erroneous results in your subsequent experimentations. By purifying your DNA samples, you reduce the probability that such things will happen and you can better preserve the quality and purity of your nucleic acids.

DNA Purification – The Fundamental Steps Involved in the Process

Basically, you can purify your DNA samples by lysating your cell and/or tissue samples using the most appropriate procedure (mechanical disruption, chemical treatment or enzymatic digestion), isolating the nucleic acids from its contaminants and precipitating it in a suitable buffer solution.

There are a number of techniques used in purifying genomic and plasmid DNA samples. These include the following:

  • Salting out using an appropriate cosmotrope such as potassium acetate

  • Extraction using organic solvents and chaotropes (guanidium salts)

  • Glass milk/silica resin-based strategies

  • Anion exchange strategies

  • Hydroxyapatite-based strategies

  • Cesium chloride (CsCl) purification

  • Affinity techniques using triple helix affinity resins and/or chemically modified silica resin

Since there are a lot of techniques to choose from, you should take the following criteria into consideration to determine the most suitable purification method for your sample:

  • Target nucleic acid

  • Source organism and starting material

  • Desired results

  • Downstream application

To make the process less time-consuming, biochemical companies developed genomic isolation kits that will suit a wide array of applications. There are also a number of products available for the isolation, transformation and high throughput screening of plasmids.

Topics: Molecular Biology

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CB™ PROTEIN ASSAY: A Bradford Protein Assay

CB Protein Assay Graph

An improved Coomassie Dye based protein assay based on the Bradford Protein Assay. This assay is suitable for the simple and rapid estimation of protein concentration. This assay is based on a single Coomassie dye based reagent. The binding of protein to the dye results in a change of color from brown to blue. The change in color density is proportional to protein concentration. Protein estimation can be performed using as little as 0.5µg protein.

Features

  • Sensitivity: Linear responses over the range of 0.5µg-50µg protein
  • Flexible Protocols: Suitable for tube or Titer plate assays
  • Ready to use assay reagents and no preparation required
  • Long shelf life, stable for 12 months
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