Molecular cloning is a commonly used technique for the generation of recombinant proteins.  The gene for a protein of interest is cloned into a vector, or plasmid, in frame with the gene for a protein tag.  These tags are used to purify expressed protein by established methodologies.  The most common tags in use consist of the six histidine motif (6XHis), purified on a nickel metal chelating column; the glutathione S-transferase (GST) tag, purified with a glutathione resin; and the calmodulin binding peptide (CBP) tag, isolated with calmodulin resin.
The Recombinant Protein Purification kit teaches students the basic principles of purifying recombinant proteins and has a hands-on lab activity that teaches students the purification of a tagged protein.  The recombinant protein supplied is a light emitting protein that allows for easy detection of the purified protein, using UV light.  Students will learn about protein tags and affinity chromatography.