Saturday, May 2, 2020

Principle and applications of affinity chromatography

Affinity chromatography is a kind of liquid chromatography that is used for separation and purification of molecules in a particular technique. It uses a reversible biological interaction called affinity which applies to the different degrees of forced attraction used by the atoms, which allows them to remain in combination. Contrasting to other chromatography-based purification techniques, which isolate the molecules based on the size (size-exclusion chromatography) or the ionic interactions strength with a stationary phase (ion-exchange chromatography), affinity purification workings by controlling of properties and particular binding interactions amongst molecules to purify the protein.

Principle of affinity chromatography:
Affinity chromatography is one of the most effective chromatographic processes for the separation of analytes from the sample mixture. It depends on particular biological interactions between two analytes, for example, antibodies and antigens, enzyme-substrate interactions, receptor, and ligand. The stationary phase in affinity chromatography consists of a cellulose beads support medium on that the substrate is covalently attached to expose the reactive groups required for enzyme bonding. When the sample protein mixture is passed into the column, the protein binds to the stationary phase with an immobilized substrate site to the stationary phase, while all other sample analytes are eluted at void volume in the column.
Biomolecules are purified by a purification method that differs according to differences in precise properties as follows.
Property:                                                         Method:
Biorecognition (ligand specificity)-Affinity chromatography (AC)
Charge -                                                Ion exchange chromatography (IEX)
Size -                                                     Size exclusion chromatography (SEC) or gel filtration (GF)
Hydrophobicity -                                Reversed-phase chromatography (RPC)
The different components essential to perform the process are as follows.
Matrix: It is passive support that can be directly or indirectly linked to a ligand.
Spacer arm: It is used to increase the binding amongst the ligand and the target molecule by eliminating any satirical hindrance effect.
Ligand: It refers to an analyte that binds in contrast to a specific target molecule.
The processes involved in affinity chromatography are as follows. 
1. Column Preparation:
2. Equilibration:
3. Sample Loading:
4. Elution of Ligand-Molecule:
5. Re-equilibration:

Applications of affinity chromatography:
  • The major application of affinity chromatography is that it is used for separation and purification of all biological macromolecule.
  • Affinity chromatography is an adaptable and valuable separation technique for pharmaceutical and biomedical analysis.
  • Affinity chromatography is used to isolate and purify enzymes, antibodies, and nucleic acids.
  • It is used in several types of clinical applications.
  • Affinity chromatography is used to purify and concentrate on an enzyme solution.
  • Affinity chromatography used in analytical chemistry to studying the kinetics of biological interactions.
  • This can be used to reduce the number of unnecessary substances in the sample mixture.
  • It is often selected method for purification of biomolecules due to its ease of operation, specificity, yield, and throughput.
  • It is used for purification and concentrates the substance from a sample mixture into a buffering solution.

Commonly asked questions on chromatography are as follows.

What type of chromatography is an affinity chromatography?
Affinity chromatography is a kind of liquid chromatography, which is used for the purification of particular biomolecules, including proteins.
 
What is the basis for the separation of proteins by the technique affinity chromatography?
Affinity chromatography isolates the proteins based on interactions between a specific ligand and a protein.
 
What is the purpose of affinity chromatography?
Affinity chromatography can be used to purify and concentrate an enzyme solution, reduce the number of unwanted components in a sample mixture, purify, and concentrate a component from a sample mixture into a buffering solution.

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