Describe what type of gel should be used to visualize the fo

Describe what type of gel should be used to visualize the following groups of proteins. Make sure to describe how that type of gel works and why you chose it. Then describe how the protein of choice could be purified. Make sure to describe every step of the purification process with your reasoning.

a) Protein A is 30kDa with a pI of 6. Protein B is 60kDa with a pI of 6. Purify protein B.

b) Protein C is 20kDa with a pI of 4. Protein D is 20kda with a pI of 7. Purify protein C

c) Protein E is 80kda with a pI of 8 and binds glucose. Protein F is 40kDa with a pI of 5 and does not bind glucose. Protein G is 80kDa with a pI of 5 and binds glucose. Purify protein G

Solution

A) both protein A and protein B have same pI value but different sizes. SDS- PAGE could be used to separate proteins based solely on their sizes. Larger protein B remains close to the point of origin, while smaller protein A moves farther down the gel.

B) two proteins differing in their pi values can be separated by isoelectric focussing. Here, the gel contains a stable pH gradient. Protein C with pI 4 would have no net charge at pH would stop at pH 4 on the gel. Whereas, protein D would stop at pH 7.

C) 2 dimensional electrophoresis is the best option. In the first dimension, based on isoelectric point, protein E would form a band at pI 8, whereas protein G and protein F with same pI would be form a single band.

In second dimension, protein F and protein G are separated based on their sizes. Protein F would move farther down, while protein G forms a band near to the point of origin.