Affinity Chromatography - Department of Molecular and Cellular ...

Chapter 3
Purification of specific groups of molecules
A group specific medium has an affinity for a group of related substances rather than for a
single type of molecule. The same general ligand can be used to purify several substances
(for example members of a class of enzymes) without the need to prepare a new medium
for each different substance in the group. Within each group there is either structural or
functional similarity. The specificity of the affinity medium derives from the selectivity of
the ligand and the use of selective elution conditions.
Immunoglobulins
The diversity of antibody-antigen interactions has created many uses for antibodies and
antibody fragments. They are used for therapeutic and diagnostic applications as well as for
immunochemical techniques within general research. The use of recombinant technology
has greatly expanded our ability to manipulate the characteristics of these molecules to our
advantage. The potential exists to create an infinite number of combinations between
immunoglobulins and immunoglobulin fragments with tags and other selected proteins.
A significant advantage for the purification of antibodies and their fragments is that a great
deal of information is available about the properties of the target molecule and the major
contaminants, no matter whether the molecule is in its a native state or has been genetically
engineered and no matter what the source material.
The Antibody Purification Handbook from Amersham Pharmacia Biotech presents the
most effective and frequently used strategies for sample preparation and purification of the
many different forms of antibodies and antibody fragments used in the laboratory.
The handbook also includes more detailed information on antibody structure and
classification, illustrated briefly here in Figures 9 and 10.
Fig. 9. H2L2 structure of a typical immunoglobulin.
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