Affinity chromatography, utilizing

Unlike other chromatographic techniques, which effect separation of species in a mixture on the basis of some physico-chemical property such as charge or molecular size, affinity chromatography utilizes the specific biological functional characteristics of the species. This gives the worker an additional parameter upon which to effect separation and, further, a parameter that is generally specific and often unique for that species. 

Affinity chromatography A form of chromatography in which separation is achieved by utilizing highly specific biochemical interactions, such as steric-or charge-related conditions, between me analyte and a molecule immobilized on a column. It is different from most forms of chromatography in mat analytes do not continuously elute from me column - only mose mat interact wim me stationary phase are retained and mus separated from omer components of me mixture under investigation. These immobilized materials are eluted from me column after all omer materials have been removed. 

It is not normally prudent to employ biospecific affinity chromatography as an initial purification step, as various enzymatic activities present in the crude fractions may modify or degrade the expensive affinity gels. However, it should be utilized as early as possible in the purification procedure in order to accrue the full benefit afforded by its high specificity. 

Although lectin affinity chromatography may be utilized to purify a variety of glycoproteins, it has not been widely employed for a number of reasons ... 

Enz)mies, inhibitors, cofactors, nucleic acids, hormones or cell chromatography can also be utilized as ligands in bioaffinity chromatography types. Examples of these methods include Receptor Affinity Chromatography and DNA Affinity Chromatography [21]. 

In the downstream processing of bioprocesses, fixed-bed adsorbers are used extensively both for the recovery of a target and for the removal of contaminants. Moreover, their performance can be estimated from the breakthrough curve, as stated in Chapter 11. The break time tg is given by Equation 11.13, and the extent of the adsorption capacity of the fixed bed utilized at the break point and loss of adsorbate can be calculated from the break time and the adsorption equilibrium. Affinity chromatography, as weii as some ion-exchange chromatography, are operated as specific adsorption and desorption steps, and the overall performance is affected by the column capacity available at the break point and the total operation time. 

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