Lecture 13 Flashcards
What were common sources for therapeutic proteins, what technology has replaced this?
non human sources like L-aspariginase from E.coli, insulin from cattle/hogs, toxins from things like snakes, bees etc.
Human sources include many blood proteins but also things like growth hormone, these have been replaced by recombinant technology. This is due to many factors (needing a large amount of donors to get the proteins, one pathogen containing sample will contaminate the bunch as well as tissue availability)
How does recombinant technology work?
Take the DNA which codes for the protein wanted and place it inside another organism in order to grow as much as you need (typically done using bacteria).
The process involves transforming bacteria with vectors and add inducers to initiate protein synthesis, different polypeptide chains for the same protein must be done in different bacteria, this is because the conditions arn’t right to join them in the bacteria.
What are the pros and cons of prokaryotic systems or recombinant technology? What is an example of a eukaryotic system often used?
pros: relatively low coost, high yielf, pathogen free
cons: protein often only partially folded and inability to perform post translational modifications.
The chinese hamster is an example of a eukaaryotic system.
What is erythropoietin? What often occurs in cancer patients with regards to this?
Erythropoietin is a small protein (163 AA) comprised of hour alpha helices, it is a hormone produced mainly in the kidney. It stimulates the synthesis of red blood cells and haemoglobin and its synthesis and release is regulated by blood oxygen levels.
Renal failure can cause a decrease in levels of this, leading to anaemia and hence is often replaced in cancer patients
What are recombinant antibodies? What are two common examples of targets?
Recombinant antibodies are becoming increasingly more used as therapeutic agents, these are used commonly to block various proteins or receptors in the body, common examples of targets are cancer or the immune system.
These can limit the effects of some diseases by preventing the disease from activating receptors or stopping the antigen.
How are therapeutic antibodies made?
What is a common problem? How is this fixed
⦁ in general antibodies are produced by injecting the antigen into the host, harvest and immortalise white blood cells (by fusing with a tumor cell to form a hybridomas) and then select for the antibodies which react to our antigen. This can often be problematic because it often uses things like mice, our bodies will react to the mouse version of the antibody and destroy it. To deal with this we add in the human comman antibody form (constant region), some mouse part is left in in the variable region.
What is anti thrombin? How is it isolated
⦁ Anti thrombin is a protein which prevents formation of thrombin in the clotting factor, without it it increases the risk of inappropriate blood clotting. Deficient individuals recieve it when undergoing surgery or giving birth (high risk of blood clots). For this protein it is added to the milk specific region in the DNA of goats, this anti thrombin can then be purified from other milk proteins.
What are the main methods of extracting growth hormone?
⦁ The pituitary gland is a source of growth hormone but not much, you need many to treat one patient. Most produced today is produced in E.Coli and doesn’t require glycolysation. A new possible method is adding a promoter in the bovine beta casein, to transgene the human growth hormone into cow embryos and then milk the cows.
