How Things Are Made/Medicine/Insulin

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Frederick Banting , discoverer of Insulin
Advertisement of insulin from cow pancreas
Insulin medicine with the hypodermic needle jab
Structures of insulin

Insulin is a hormone produced by the pancreas cells, called the islets of Langerhans. that helps regulate the levels of sugar (glucose) in the blood. It does this by enabling the cells in the body to take in and use glucose for energy. Insulin is essential for the body to function properly, as it helps the body use and store the energy it gets from food. These cells continuously release a small amount of insulin into the body, but they release surges of the hormone in response to a rise in the blood glucose level.

When you eat, your body breaks down the carbohydrates in your food into glucose, which enters your bloodstream and raises your blood sugar level. In response, the pancreas releases insulin into the bloodstream, which helps the cells in your body take in the glucose and use it for energy. Insulin also helps the liver store excess glucose as glycogen, which can be converted back into glucose as needed. People with diabetes have difficulty producing or using insulin properly, leading to high blood sugar levels. This can be managed through insulin injections, oral medications, and lifestyle changes such as diet and exercise.

Before researchers discovered how to produce insulin, people who suffered from Type I diabetes had no chance for a healthy life. Then in 1921, Canadian scientists Frederick G. Banting and Charles H. Best successfully purified insulin from a dog's pancreas. Researchers continued to improve insulin but the basic production method remained the same for decades. Insulin was extracted from the pancreas of cattle and pigs and purified. The chemical structure of insulin in these animals is only slightly different than human insulin, which is why it functions so well in the human body.

What do we need to make this thing?

Escherichia coli - Insulin is traditionally produced by extracting it from the pancreases of pigs or cows. However, this process is expensive and can be unreliable, as the supply of animal insulin is limited.

As a result, researchers have developed methods for producing insulin using biotechnology, called recombinant insulin. Recombinant insulin is identical to the naturally occurring hormone and has the same properties and effects in the body. Human insulin is grown in the lab inside common bacteria.

Escherichia coli is by far the most widely used type of bacterium, but yeast is also used. The bacterium are then grown in large fermentation tanks, where they produce and secrete insulin into the surrounding medium. The insulin is then purified and processed for use in medical treatment. It is also relatively cheap and efficient to produce large amounts of insulin using this method.

Recombinant insulin has several advantages over traditional animal-derived insulin. It is purer and more consistent, as it is produced in a controlled environment using a standardized process. It is also more widely available and can be produced in larger quantities to meet the demand for insulin.

What is the step by step process?

Step 1: The insulin gene is a protein consisting of two separate chains of amino acids, an A above a B chain, that are held together with bonds. Both insulin genes is extracted from stem cells of healthy human pancreas using restriction enzymes.
Step 2: Using same restriction enzymes, plasmids are cut open for the insulin genes to attach to.
Step 3: These two insulin genes are then inserted into plasmids, small circular pieces of DNA that are more readily taken up by the host's DNA. This is called recombinant plasmids. The insulin and plasmid are sealed up using a special enzymes called ligase
Step 4: The recombinant plasmids are inserted into a non-harmful type of the bacterium of E. coli using a process called transfection.
Step 5: The bacteria synthesizing the insulin then undergo a fermentation process. They are grown at optimal temperatures in large tanks in manufacturing plants.
Step 6: After growing, the cells are taken out of the tanks and broken open to extract the insulin genes using multiple chemicals. First, add a mixture of lysozome that digest the outer layer of the cell wall, second adding a detergent mixture that separates the fatty cell wall membrane. Third, adding cyanogen bromide, a reagent that splits insulin chains from the plasmid chains
Step 7: The two insulin gene chains are then mixed together and joined by disulfide bonds through the reduction-oxidation reaction. An oxidizing agent (a material that causes oxidization or the transfer of an electron) is added.
Step 8: The DNA mixture is then purified so that only the insulin chains remain. Manufacturers can purify the mixture through several chromatography, or separation, techniques that exploit differences in the molecule's charge, size, and affinity to water. Some of techniques are ion exchange column, reverse-phase high performance liquid chromatography, and a gel filtration chromatography column. Manufacturers can test insulin batches to ensure none of the bacteria's E. coli proteins are mixed in with the insulin. They use a marker protein that lets them detect E. coli DNA. They can then determine that the purification process removes the E. coli bacteria.

Overall view on how to make an insulin, enlarge to see in details