5: mila Flashcards
What are main mechanisms of protease inhibition?
- Canonical inhibitors - inhibitor binds like substrate and blocks activity
- Exocite-binding inhibitors - binds close to active site and blocks it
- Quasi-substrate inhibitors - combination of prior two types
- Allosteric inhibitors - binds away from active site, prevents dimerisation or protease activation
Why is there a need for endogenous protease inhibitors; mention one example of this.
- to ensure proteases are not breaking down proteins when the protein is needed
- Serpins - inhibit serine proteases
- Cystatins, calpains and IAP family inhibit cysteine proteases
- RnBP inhibits renin (an aspartate protease)
- TIMPs inhibit metalloproteases
How come the number of endogenous inhibitors is so much smaller than the number of endogenous proteases?
- not completely specific, and can bind multiple proteases, some proteases may not be able to be inhibited by protein
What are serpins and what is the main catalytic group they act on?
- endogenous protease inhibitor
- serine proteases
What is the main endogenous inhibitor acting on thrombin?
- Serpin C1, controlling blood coagulation
What is the function of the HIV-1 protease and what is the benefit of inhibiting this?
- cleaves polyprotein chains into functional HIV proteins
- without this the HIV cannot produce a new functioning generation of viruses
What key factors need to be considered when designing a pharmacological PI?
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Why is it necessary to include protease inhibitors when working with biological samples in the experimental situation?
- prevent endogenous molecule under study being degraded when it is out of its usual cellular compartmentalisation and regulation
What aspects need to be considered when choosing which PIs to include in biological sample experiments?
- What type of proteases may target molecules of interest
- Temperature of activation
- If the experiment will use a type of protease - this should then not be inhibited
