Proteins are the most important component of the cells of the human body. Almost all the functions of the body depend on these components. They are combined with the complex organic molecules and are composed of chains of amino acids. We can say that amino acids are the building blocks of proteins. In our body, proteins perform various basic functions for example they determine the color of the eye and composition of the nails, hair, skin and even the construction of immune system is done by different complex structures of proteins. Before the discovery of DNA, scientists used to consider proteins as the carriers of genetic material. But the discovery of DNA proved it wrong.
Production of Recombinant Proteins in Mammalian Cells:-
Recombinant proteins are produced using the recombinant DNA techniques. These techniques make possible to produce proteins in large quantities. The production of proteins is very important because they perform many important functions and can be used in the industrial production and also can be used for the laboratory purposes. The production of recombinant proteins takes place through over expression. In this technique, proteins are produced in large quantities in the form of vectors. If the proteins are to be produced at small scale then bacteria or yeast are used as the host cells, but on large scale production of recombinant proteins takes place in the mammalian cells. There is an advantage of mammalian cells that they can produce good secretory proteins, the expression of which is very difficult to determine in small species. Following are the steps which are involved in the recombinant protein production:
1) By using the mammalian cells as a host, cDNA which is encoding the protein of interest is cloned and converted into an expression vector.
2) The vector which is produced injected into the mammalian cells. Now stable clones will be produced in the cells. The clones can be analyzed by MPE or by any other method.
3) Now that clone is selected which has the high tendency of producing recombinant proteins. This clone is placed in the medium which is without serum.
4) After the clone is placed in the serum free medium, it is now run in the bioreactor. Due to this, the clone is now able to produce recombinant proteins in large quantities without any difficulty.
Production of Recombinant Proteins in Bacteria:-
If the production of the recombinant takes place in bacterial cell, then there should be some precautionary measures that the protein should not be produced in large quantities, otherwise it will become toxic and will stop the production of bacteria. The proteins which are produced in the bacterial cell can be purified by tagging the protein clones. These proteins bind to the special matrix through which they can b recognized. Due to this matrix, the recombinant protein will easily come out of the cellular fragments. For example, if the protein is tagged with histidine, it will bind to the column of the nickel. Due to the binding of the protein to the nickel, it will be easy to cut the recombinant protein. But bacterial cells allow the production of only small amount of recombinant proteins.
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