Question

The gene for a eukaryotic polypeptide hormone was isolated, cloned and over-expressed in a bacterium. After the polypeptide was purified from the bacterium, it failed to function in the organism from which the gene was isolated. Suggest all the possibilities why the recombinant protein was inactive.

Answer 1

• To have proper three dimensional folding. 
• Removal of introns is not there in the prokaryotes as they lack intron removal machinery. 
• Modification of proteins (Post-translational modification) is not there.