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Western Blot Protein Length

  1. Aug 30, 2011 #1
    Hello Forum,

    please take a look at this image


    It shows a Western blot of an extract of proteins.

    My question is how can you determine the length of both proteins A and B graphically?

    Could you please help me?
  2. jcsd
  3. Aug 30, 2011 #2

    Andy Resnick

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    ITYM 'mass' of the protein. IIRC, the mass scale is set using the ladder (the set of spots on the left), and the masses of unknown proteins is then read off the scale.
  4. Aug 30, 2011 #3


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    The distance migrated by proteins in an SDS-PAGE gel is related to the logarithm of the molecular weight. So, you can measure the distance migrated from the bottom of the well for each of the protein standards in lane 1, plot these distances versus the logarithms of their molecular weights, and find the best-fit line. This best-fit line can then be used to estimate the molecular weights of your samples in lane 2.
  5. Aug 30, 2011 #4
    Thank you for your answers.
  6. Aug 30, 2011 #5
    Thank you for your answer.

    I read on other websites that I have to measure the distance from the side above from where the proteins started.

    How can I plot the distances and their molecular weights? Can you tell me step-by-step please?
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