Producing useful proteins
Recombinant DNA technology can be used to make cells produce proteins encoded by introduced genes. Recombinant proteins can be produced using microorganisms such as bacteria and yeast, or using animal cells grown in culture.
For some human proteins, eukaryotic host cells are particularly useful because their cell machinery can carry out post-translational modifications required to produce a suitable protein.
Large-scale production of recombinant proteins can provide:
- a reliable supply of the required protein
- production of large quantities at relatively low cost
- proteins that are identical to human proteins or have useful modifications
- an alternative to obtaining therapeutic proteins from animals or donated human material.
Recombinant insulin
- A plasmid is modified to contain the human insulin gene.
- The recombinant plasmid is introduced into bacterial cells by transformation.
- Successfully transformed bacteria are identified and placed under suitable culture conditions.
- The bacteria multiply and express the insulin gene.
- The resulting insulin is extracted and purified.
Recombinant insulin provides a dependable source of human insulin without relying on insulin obtained from cows or pigs. It can also reduce problems associated with reactions to animal-derived insulin.
Factor VIII
Factor VIII is a protein involved in blood clotting and can be produced for haemophilia treatment using genetically modified hamster cells. These cultured cells express the protein, which can subsequently be isolated and purified.
This method reduces dependence on Factor VIII obtained from donated human blood and therefore lowers the risk of transmitting infections through blood-derived material.
Exam Tip: When explaining an advantage of a recombinant protein, connect the production method to its consequence. For example, culturing genetically modified cells can provide a dependable supply without relying on animal tissue or donated blood.