Recombinant DNA technology and therapeutic proteins
One of the main discoveries in r-DNA technology was the production of biosynthetic human insulin, which was the rst biomolecule made through r-DNA technology. Later on, this bioengineered insulin became the rst biotechnology product approved by the U.S. Food and Drug Administration (FDA). It has been reported that insulin is basically an ideal candidate because it is a relatively simple protein and is therefore relatively easy to manipulate for genetic engineering. The rst step in making recombinant insulin is the introduction of a specic gene sequence (oligonucleotide) that codes for insulin production in humans into the bacteria E. coli; it has been reported that only 0.94% of bacteria can pick up the sequence. Nevertheless, because the life cycle of E. coli is only about 30 min, there is no problem in generating a million copies of E. coli in a short period of time to be used for inducing insulin production.