Final answer:
Humulin, a synthetic human insulin, is a protein made by recombinant DNA technology involving the synthesis of A and B chain DNA sequences, expression in E. coli, and subsequent purification and reassembly. It helps in treatment of type 1 diabetes.
Step-by-step explanation:
Humulin, or synthetic human insulin, is a protein molecule that is created through recombinant DNA technology. The process involves the synthesis of DNA sequences corresponding to the A and B chains of insulin. Each chain is constructed from amino acids, with the A chain comprising 21 amino acids and the B chain containing 30. To manufacture humulin, DNA sequences encoding these chains are chemically synthesized, with the required numbers of nucleotides for each chain being 63 and 90 respectively, plus a signal for protein synthesis termination.
The synthetic A and B chain genes are subsequently inserted into a bacterial enzyme known as ß-galactosidase. This recombinant DNA is then introduced into E. coli cells, which express the insulin gene as the cell replicates. Following expression, the A and B chains are extracted, purified, and recombined to form the mature insulin protein with disulfide cross bridges creating the full three-dimensional structure essential for biological activity.
Once synthesized, humulin can then enter clinical use, providing a vital treatment for people with type 1 diabetes, whose bodies are unable to produce insulin naturally due to a mutation in the insulin gene. The introduction of humulin revolutionized diabetes treatment, as it was a major improvement over previous insulin sources such as bovine or porcine insulin.