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==Introduction== | ==Introduction== | ||
− | + | For Western blot analysis, a high quality antibody can have a relatively low affinity for its target protein. This is because the target is localized and concentrated on a blot, allowing the antibody to bind using both antibody “arms” thereby strengthening the association. Even an antibody that is loosely bound to the blot under these circumstances may dissociate then re-associate quickly since the local concentration of the target protein is high. The lower limit for protein detection is approximately 1 ng/lane, a value that varies with the size of the protein to be detected and the Western blotting apparatus that is used. For most polyacrylamide gels, the protein capacity for each lane is 100 to 200 μg (that would be 20 μL of a 5-10 μg/μL protein preparation). Thus, 1 ng represents a protein that is approximately 0.0005-0.001% of the total cellular protein (1 ng out of 100,000-200,000 ng). Proteins that make up a more significant fraction of the total protein population will be easier to detect. | |
==Protocols== | ==Protocols== |
Revision as of 16:50, 30 August 2019
Contents
Introduction
For Western blot analysis, a high quality antibody can have a relatively low affinity for its target protein. This is because the target is localized and concentrated on a blot, allowing the antibody to bind using both antibody “arms” thereby strengthening the association. Even an antibody that is loosely bound to the blot under these circumstances may dissociate then re-associate quickly since the local concentration of the target protein is high. The lower limit for protein detection is approximately 1 ng/lane, a value that varies with the size of the protein to be detected and the Western blotting apparatus that is used. For most polyacrylamide gels, the protein capacity for each lane is 100 to 200 μg (that would be 20 μL of a 5-10 μg/μL protein preparation). Thus, 1 ng represents a protein that is approximately 0.0005-0.001% of the total cellular protein (1 ng out of 100,000-200,000 ng). Proteins that make up a more significant fraction of the total protein population will be easier to detect.
Protocols
Part 1: Lyse cells
Part 2: Electrophorese cellular proteins
Part 3: Transfer proteins to membrane
Reagents list
Next day: Complete antibody staining for Western blot analysis