Biochemical defense Flashcards
Explain how the cells can produce so many different antibodies with many fewer genes?
Genetic recombination. The combination between different types of variable and joining regions and the constant region makes a lot of different combinations possible. The heavy chain also has variable and constant regions with even more combinations possible, and can bind to any light chain(?) making a lot of combinations possible
How does antibodies bind to antigens?
The variable site on the light and heavy chains will interact with the antigen, with ionic, hydrogen-bonding or hydrophobic interactions. It can also slightly change to induce a better fit
How can you use antibodies as protein purificiation or identification?
Add antibodies to a column -> will hold onto their specific proteins while other wash through.
Attach radioactive tag to antibody so it will send out signal when attached to its protein (can work even in cells)
Immunoblot assays - see if you have the chosen protein and how big it is (transfer from SDS gel to nitrocellulose membrane, block other proteins from getting to surface, IgG against protein IgG against IgG + enzyme that change colour in response to substrate
What does cytochrome P450 do?
Oxidations into non polar compounds to increase water soluability and facilitate excretion
What is bioactivation?
Formation of harmful or highly reactive metabolic from relatively inert/nontoxic chemical compound
(old exam question) Describe the principles behind the analysis technique ELISA?
Proteins in sample are added to a surface (wells) and the wells are then blocked to prevent future protein-binding. The solutions are then treated with a primary antibody and then washed. A secondary antibody linked with an enzyme that catalyzes a reaction to form a colored product is then introduced. This is washed again and substrate is added. Color intensity is proportional to the concentration of protein in sample
Why are polycyclic aromatic hydrocarbons dangerous?
They can be “activated” by CYTP450 to reactive epoxides that can bind to DNA to form adducts - in the wrong genes (such as tumor suppresing genes) this is very dangerous
Why are -SH groups good for reduction reactions?
High reactivity
What are phase I reactions?
Reduction, oxidation or hydrolysis reactions to increase water soluability.
What are phase II reactions?
Conjugation, acetylation, sulfation to further increase soluability.
Benzo(a)pyrene
A part of the class polycyclic aromatic hydrocarbons, comes from cigarette smoke. Gets bioactivated by phase I and phase II reactions, cancerogenic intermediates
