Is insulin a recombinant protein?

Yes, insulin is considered a recombinant protein and was the first drug that was created with recombinant DNA to be licensed and marketed. Insulin is composed of 51 amino acids. Insulin contains two polypeptide chains linked by disulfide bonds, and thus two pieces of DNA are extracted during the recombinant DNA processes. The DNA strands are then placed into two different plasmids, which are cut with restriction enzymes. Next, the plasmids are incubated with a strain of E. coli, and the bacteria that actively take up the plasmid will continue to grow on a plate. Once they grow and replicate, it allows the plasmid and insulin gene to replicate millions of times. The bacteria are then given a signal to produce the protein insulin, which is then produced and purified for human use. Synthetic insulin is made both in bacteria and yeast.