Protein Purification: Pulling It All Together

Pulling It All Together

The techniques introduced are the backbone of the modern biologically based sciences, and they will be seen often throughout this book along with the information gleaned from their use. This could not be any more true than for the current trend known as proteomics. Proteomics is the systematic analysis of an organism’s complete complement of proteins, its proteome, and it is one of the fastest-growing fields. They created proteins they called “the bait,” shown as protein 1 in the figure. These were tagged with an affinity label and allowed to react with the other cell components. The tagged bait proteins were then allowed to bind to an affinity column. In binding to the column, they took any other bound proteins with them. The bound complex was eluted from the column, then purified with SDS–PAGE. The bands were excised and digested with trypsin. After digestion, the pieces were identified with mass spectrometry. In this way the identities of the proteins associated with the bait protein were established.