Genetic engineering steps Involved

Fig. 14 Reaction steps involved in the surface modification process, (a) Coupling of biotin to the SAM of cysteamine through EDC catalyzed amidation. (b) Binding of streptavidin to the preformed biotin layer, (c) Binding of the glutamate transporter to the streptavidin/biotin layer via the genetically engineered strep-tag at the N-terminus of the membrane protein. [Reprinted from ref 100 by permission of the Royal Society of Chemistry copyright 2008.]...

Purification of peptides by immobilized enzymes is a relatively recent approach that may have a potential use in the purification of genetically engineered proteins. Purification of recombinant proteins is often difficult and involves many purification steps for a very low yield. Smith et al. found that a specific metal-chelating peptide on the NH2 terminus of a protein can be used to purify that protein with immobilized ion affinity chromatography. The nucleotide sequence that codes for the expressed protein is extended to include codons for the chelating peptide. This concept of amino acid addition to recombinant proteins can also be beneficial in protein purification by affinity chromatography with immobilized enzymes. 

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