Proper folding of proteins requires reduced glutathione. Oxidative stress or glutathione deficiency (including potentially cofactor depletion like lipoic acid) make this a big issue. I have been talking about possible misfolded mitochondrial proteins for decades now. The total amount of the proteins can be normal or even high, but how much is working?
But oxidative stress would surely affect other proteins as well as the mitochondrial ones? It does not discriminate.
Surely it would 'discriminate' in that components that are more active would be affected more?
I'm not sure level of activity changes how a protein will be affected by free radicals. Fatty acids (unsaturated ones are most prone to this) are not enzymatically active for example, but can still be oxidized, because of their chemical properties. Mitochondrial membranes could be affected before their proteins, it depends on how stable the proteins are (I have no idea about the stability of mitochondrial proteins).
Yes, but the highest concentration of oxidative stress as free radicals would be inside the mitochondria.
Sorry I've just been through exam season and my mental fatigue is adding up. When you are talking about folding and reducing environments, do you mean how it affects disulfide bridges in the protein? A lack of reduced glutathione > oxidized cysteines and formation of disulfide bonds? I'm not familiar with reduced glutathione in regards to protein formation. Please tell me more, my protein structure class was not very in-depth and I've come to realize how little chemistry I've had in cell biology and biochemistry previously
They could change protein folding, yes. But if the premise is that protein levels has been measured this should've been picked up? There are at least one or two old studies that has looked at heat shock proteins. I wish someone else would pick up on this.
Yes.
Some proteins need the disulfide bridges created in an oxidative environment, though. So saying that correct folding of proteins (like in "all proteins") requires reduced glutathione feels like a stretch to me, although it's not my area.