{*Figure 1*}Protein/Enzyme Purification -- PART I
Section A
Proteins fold into a specific shape or 3-D conformation:
{*Figure 1*}
Purification of a protein depends on this unique shape,
which determines both its Biological Function and properties in solution.
Protein purification objective:
To separate one protein from a complex mixture of proteins (such as a tissue extract),
while maintaining Biological Function .
One can maintain biological function by controlling the pH,
the temperature and the ionic strength (ie salt concentration).
To purify a protein you need:
1. Unique assay (a test) for the protein of interest
2. Assay for total protein
3. A series of separation steps adapted to the protein
4. Assays for purity
If the protein you want to purify is an enzyme
its biological activity is used as a unique assay for its presence in a tissue extract.
To purify the protein you use methods based on differences in:
1. Surface charge on proteins
2. Molecular size of protein (related to molecular weight)
3. Biological activity due to binding to substrates or inhibitors
Return to Lecture 6 -- HOME PAGE
©Wilbur H. Campbell, 1995; wcampbel@mtu.edu