Recombinant DNA Technology in Details for Human Insulin Production

Insulin is an essential hormone for regulating blood sugar levels, and its deficiency leads to Type 1 diabetes. Before the development of recombinant DNA technology, insulin was extracted from the pancreas of cattle and pigs. However, animal insulin had slight structural differences from human insulin, which sometimes led to allergic reactions in patients.

With advances in genetic engineering, scientists developed recombinant human insulin, which is now mass-produced using bacteria (E. coli) or yeast (Saccharomyces cerevisiae). This breakthrough revolutionized diabetes treatment by providing a safe, effective, and abundant source of insulin.

What is Recombinant DNA Technology?

Recombinant DNA (rDNA) technology involves combining DNA from different sources to produce specific proteins. In insulin production, scientists insert the human insulin gene into bacteria or yeast cells, enabling them to produce human insulin identical to naturally occurring insulin.

Steps in Recombinant Insulin Production Image from: Biotechnology - Health and Medicine

Steps in Recombinant Insulin Production

1. Isolating the Human Insulin Gene

• The gene for human insulin is identified and isolated from pancreatic cells or synthesized in the lab.

• Since insulin is a protein, scientists use mRNA from pancreatic cells to create a complementary DNA (cDNA) copy of the gene.

2. Inserting the Insulin Gene into a Plasmid

• A plasmid (a small, circular DNA molecule found in bacteria) is used as a vector to carry the insulin gene.

• Restriction enzymes (endonucleases) are used to cut the plasmid at a specific site.

• The human insulin gene is then inserted into the plasmid using DNA ligase, forming a recombinant plasmid.

3. Transforming Bacteria or Yeast Cells

• The recombinant plasmid is introduced into E. coli (bacteria) or Saccharomyces cerevisiae (yeast) through transformation.

• The genetically modified bacteria or yeast incorporate the insulin gene into their cells and begin producing insulin.

4. Large-Scale Fermentation

• The transformed bacteria or yeast are grown in large bioreactors, where they multiply and produce insulin.

• Fermentation conditions (temperature, pH, nutrients) are optimized to maximize insulin production.

5. Extraction and Purification

• The insulin protein is extracted from the bacterial or yeast cells.

• It undergoes purification to remove any unwanted bacterial components.

• The purified insulin is chemically modified to match natural human insulin and formulated into injectable insulin.

Types of Recombinant Insulin

1. Short-acting insulin (e.g., Humulin R) – Works quickly and mimics natural insulin secretion after meals.

2. Long-acting insulin (e.g., Lantus, Levemir) – Modified to release slowly over time for steady blood sugar control.

3. Rapid-acting insulin analogs (e.g., Humalog, Novolog) – Modified for faster absorption into the bloodstream.

Advantages of Recombinant Insulin

✅ Identical to human insulin – Reduces allergic reactions compared to animal-derived insulin.
✅ Mass production possible – Ensures a stable and sufficient insulin supply for diabetes patients.
✅ More effective and safer – Improved absorption and better blood sugar regulation.
✅ Ethical benefits – Eliminates the need for insulin extraction from animals.

Conclusion

Recombinant DNA technology has revolutionized diabetes treatment by enabling the mass production of human insulin using genetically engineered bacteria and yeast. This advancement ensures better availability, safety, and effectiveness of insulin for diabetic patients. The future of insulin production continues to evolve with further research into gene therapy and artificial pancreas technology, aiming for even more efficient diabetes management.