Recombinant proteins Flashcards
Give 3 examples of therapeutic recombinant proteins.
- Hormones like insulin
- Vaccines
- Antibodies
What are diagnostic proteins?
Those used to determine an outcome.
Give 3 examples of diagnostic proteins.
- Enzymes
- Antibodies
- Biosensors
Commercial enzymes can be used in a) industry and b) biotechnology. Give examples of each.
a) Food production
b) Restriction enzymes, thermostable polymerases etc.
In order to recombine proteins you must first obtain pure forms of those you wish to combine. Can you get these from natural sources?
Yes if they are abundant in a particular cell or tissue.
What are 3 disadvantages to purifying proteins from natural sources?
- Cost
- Ethical considerations
- Contamination/infection
You can obtain proteins for recombination from a transformed bacterial host instead. Give 5 advantages of this.
- Produces large volumes of protein by clonal growth
- Genetic engineering allows for high expression of required protein
- Reduced cost
- Reduced risk of contamination
- More ethically acceptable
If you are transforming bacteria with eukaryotic DNA what must you use and why?
cDNA because it contains no introns.
Promoters are usually organism-specific and thus un-transferable. True or false?
True, for example a human promoter will not work in yeast.
You must always use endogenous promoters in protein production. These are not only organism specific but tissue specific as well. True or false?
True.
The genetic code is degenerate. What does this mean?
Multiple codons code for the same amino acid.
Different organisms display preference for some codons. True or false?
True - because the code is degenerate several codons produce the same AA, and some species have higher proportions of particular codons.
What is codon optimisation?
Adapting the genetic code to suit the host organism, e.g. using codons that they prefer.
Give 4 methods of delivery of synthetic genes into a host.
- Electroporation
- Chemical treatment
- Biolistics
- Microinjection
Define electroporation.
Delivering a pulse of electricity that momentarily opens the pores of a cell.
Define biolistics.
Whereby tiny metal pellets coated in DNA are propelled into living cells at high velocities.
The expression of a protein in a host does not always work as it creates negative selection against the host. True or false?
True.
Inserted proteins may not always be expressed in the host. Give 3 reasons why.
- Point mutations
- Methylation
- Chromosomal rearrangements
If the inserted protein is negatively selected for, why might it not be expressed?
Because it is unfavourable.
Expression can go wrong and result in a) degradation and b) aggregation. What does this mean?
a) Where the protein is broken down and becomes non-functional
b) Too much is produced and clumps together, also reducing function
Where is hGH produced?
In the pituitary gland.
Animal hGH is compatible with humans. True or false?
False - it was isolated from human cadavers but there were major issues with HIV and prion proteins and this is now banned.
How is hGH produced now?
With E. coli as a host.
