How did recombinant insulin become an important early product of genetic engineering?

Recombinant insulin became a landmark achievement in synthetic biology because it was the first clinically significant human protein produced as a pharmaceutical product using recombinant DNA technology.1

Before its 1982 approval, patients with diabetes relied on insulin extracted from the pancreases of cows and pigs. While these animal-derived treatments were effective for decades, the development of synthetic human insulin by Genentech Inc. allowed for the creation of a product identical to the human hormone.12

The process involved synthesizing the specific DNA sequence that codes for human insulin and incorporating it into Escherichia coli bacteria. This breakthrough demonstrated that laboratory-engineered genes could direct bacteria to manufacture complex human proteins at a scale sufficient to meet market demand. This success paved the way for the production of other vital recombinant proteins, such as human growth hormone, and established a new paradigm for medical treatment.1