Summary
An enzyme-linked immunosorbent assay (ELISA) is typicallyperformed to detect the presence and/or amount of a target proteinof interest within an experimental sample. Detection of the targetprotein is made possible by antibodies, which make the ELISA animmunoassay. Through a series of incubation and washing steps,these antibodies, which are frequently linked, or conjugated, to anenzyme, will detect protein coating the bottom of a well on amicrotiter plate. When exposed to a substrate, antibody-boundenzyme will cause a color change, thereby indicating the presenceof the protein-of-interest in the sample.
In this video, the theory behind how ELISAs work is explained,including a discussion of both primary and secondary antibodybinding and the importance of blocking steps. Theory is followed bypractice, as the video progresses to an explanation of thestep-by-step procedure. Finally, variations of the standard ELISAsuch as the sandwich and competitive ELISAs are introduced, andreal world applications of this method, such as in over-the-counterpregnancy tests are explained.
1. For which of the following applications could an ELISA beused?
- To neutralize trypsin within a sample.
- To determine the size of a plasmid within a sample.
- To determine the presence or absence of contamination within asample.
- To determine the presence or absence of a specific proteinwithin a sample.
2. The target protein is recognized by...
- ...the substrate.
- ...buffer enzymes.
-...unlabeled viral particles.
-...the primary antibody.
3. The absorbance measured for each well is _____to the amountof target protein present in
each sample. (cell culture media harvested from human anti-body-producing cell lines).
- equal
- not directly related
- inversely proportional
- directly proportional
