after incubating the protein mixture from the rat uterus with radioactive estradiol and centrifuging the mixture, what must one do?
after the centrifugation is complete, a small hole is made in the bottom of the centrifuge tube and portions of the gradient are collected and tested for radioactivity. The estradiol-estrogen receptor complex should be situated at about 4S.
However, there are other proteins in the mix that have an S value of about 4S, therefore, the fraction containing the complex also contains other proteins that need to be discarded. We can separate the complex from the other protiens by using immunological techniques