Case 7 redox signalling Flashcards
What is ROS?
oxygen centred free radicals that can cause damage to biomolecules
What is oxidative stress?
Disturbance in the balance between production of ROS and antioxidants > too much ROS
What are some sources of ROS?
- protein folding
- cyclooxygenase
- xanthineoxidase
- lipoxygenase
- mitochondrial export chain
At what step/factor can mitochondria produce O2- radical?
at I and III
What does SOD do?
converts the oxygen radical into hydrogen peroxide by adding hydrogen
What types of NOS do we have
nNOS (neuronal NOS)
iNOS (inducible NOS, immune system)
eNOS (endothelial NOS)
What is nitrosylation?
incorporation of NO into another molecule, similar to phosphorylation
What does NADPH oxidase do?
it catalyses the formation of superoxide by transferring one electron to oxygen from NADPH, causing a superoxide radical
What are the phases of the liver?
- oxidation and reduction occurs. CYP450 works here
- conjugation with gluthathione. GST and UGT work here
- ABC pump excretes the garbage
How can RNS and ROS damage the body?
- DNA damage
- protein damage
- lipid damage
What are the repair processes of the DNA?
- Base excision repair
- nucleotide excision repair
- recombinational repair
- mismatch repair
What are some non-enzymatic antioxidants
- vitamine E and C
- present in food
What are some enzymatic anti-oxidant
- SOD (superoxide dismutase)
- GGST (glutathione transferase)
- NADPH quinone oxidoreductase (NQO1 and 2)
What are the 3 types of SOD?
- manganese containing SOD
2 Copper-zinc SOD - Extracellular SOD
What are some inducers and scavengers of ROS?
inducers:
- metabolic defects
- oncogenes
- ER stress
- Hypoxia
Scavengers:
- Tumour suppressors
- dietary antioxidants
- NADPH
- glutathione
- NRF2
