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examBoard: Pearson Edexcel
examType: IGCSE
lessonTitle: Human Protein Production
Human protein production is an amazing application of genetic engineering that allows us to make human proteins using other organisms. This technology has revolutionised medicine by providing treatments for conditions like diabetes, growth disorders and blood clotting problems.
Key Definitions:
Before genetic engineering, people with conditions like diabetes had to rely on animal insulin (from pigs or cows). This sometimes caused allergic reactions and wasn't always effective. By making human proteins in bacteria or other organisms, we can produce pure human proteins that work better in our bodies and don't cause allergic reactions.
Human proteins are typically produced in special facilities called bioreactors. These are large vessels where genetically modified bacteria or yeast cells grow and produce the desired proteins. The process is carefully controlled to ensure the proteins are pure and safe for medical use.
Let's look at how scientists make human insulin using bacteria as an example:
Scientists first identify and isolate the human gene that codes for insulin. This gene contains the instructions for making the insulin protein.
Using special enzymes called restriction enzymes, scientists cut out the insulin gene from human DNA and also cut open a plasmid (a small circular DNA molecule) from bacteria.
The human insulin gene is inserted into the bacterial plasmid using another enzyme called DNA ligase, creating recombinant DNA.
The recombinant plasmid is inserted into bacterial cells (usually E. coli). This process is called transformation.
The transformed bacteria are grown in large fermentation tanks where they multiply and produce human insulin as they grow.
The insulin is extracted from the bacteria, purified and processed to make it suitable for medical use.
In 1982, human insulin became the first genetically engineered human protein approved for medical use. The product, called Humulin, was developed by Genentech and Eli Lilly. Before this, diabetic patients relied on insulin extracted from pig and cow pancreases, which sometimes caused allergic reactions. Humulin revolutionised diabetes treatment by providing a reliable source of human insulin that was identical to what the human body produces naturally.
Many important medical treatments are now produced using genetic engineering:
Used to treat diabetes. Helps control blood sugar levels by allowing cells to take up glucose from the blood.
Treats growth disorders in children and adults with growth hormone deficiency.
Helps people with haemophilia and other bleeding disorders form blood clots properly.
Stimulates red blood cell production in people with anaemia due to kidney disease or cancer treatments.
Used to treat certain cancers, multiple sclerosis and viral infections like hepatitis.
Some vaccines are now produced using genetic engineering, including the hepatitis B vaccine.
When we insert a human gene into bacteria, we're taking advantage of the fact that all living things use the same genetic code. The bacterial cell can read the human gene and follow its instructions to make a human protein.
The process of making proteins from genes involves two main steps:
The DNA sequence of the gene is copied into a molecule called messenger RNA (mRNA). This happens in the nucleus of eukaryotic cells or in the cytoplasm of bacteria.
The mRNA is read by ribosomes, which assemble amino acids in the order specified by the mRNA to form a protein. This happens in the cytoplasm.
Today, virtually all insulin used by diabetic patients worldwide is produced using genetic engineering. This has made diabetes treatment more effective and accessible. Modern insulin production has evolved to create insulin analogues - slightly modified versions of human insulin that work faster or last longer in the body. For example, rapid-acting insulins like Humalog and NovoRapid start working within 15 minutes, while long-acting insulins like Lantus can work for up to 24 hours. These innovations have dramatically improved quality of life for people with diabetes.
While human protein production has many benefits, it also raises some ethical questions:
The field of human protein production continues to advance rapidly:
Scientists are developing plant-based and cell-free systems for producing human proteins, which could make production cheaper and more efficient.
In the future, we might be able to produce proteins tailored to individual patients' needs, making treatments more effective.
Efforts are underway to make these life-saving proteins more affordable and accessible in developing countries.
Human protein production through genetic engineering has transformed medicine by providing safe, effective treatments for many serious conditions. It demonstrates how understanding DNA and genetics can lead to practical applications that improve human health. As you continue your biology studies, remember that the molecular processes you're learning about have real-world impacts on people's lives. The ability to produce human proteins in bacteria is one of the most successful applications of genetic engineering and continues to benefit millions of patients worldwide.
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