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Specificity of Albumin Binding

In this experiment we used electrophoresis to study the binding interactions that occure between serum albumin and two synthetic dyes. The dyes were Bromophenol Blue and Ponceau S. The basis for this procedure was the observation that the free dyes not bound to albumin migrate faster than albumin or dyes bound to albumin.

Important: In the electrophoresis gel there are two wells that have the number 4 tube because someone in our group accidentally filled up two of the wells with tube #4 mixture. If you have any questions please contact me.

See attached file for full problem description.


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Here's a great title for the experiment: Determining the Relative Affinities of Two Dyes, Bromophenol Blue and Ponceau S, to Bovine Serum Albumin using Electrophoresis

Explanation of the experiment:

Lane 1: We see the migration of bromophenol blue when not bound to BSA (bovine serum albumin). It migrates fairly quickly through the gel.

Lane 2: When we add BSA to the dye, we notice that the location of the dye is farther up the gel. That means that the dye has not migrated as quickly. Its movement through the gel matrix has been impeded. How come? It has become bound to BSA. This new complex (BSA-bromophenol blue) migrates slower through the gel than does bromophenol blue on its own. This demonstates a nice binding affinity between BSA and bromophenol.

Lane 3: This is much the same as Lane 2 except for the fact that we can just begin to see some excess unbound bromophenol blue appearing in the zone where free bromophenol blue migrates.

Lane 4: We'll ignore the first lane 4 and look only at the second lane 4. This clearly shows that the more ...