Uncoupler & Amt of ATP

[blazinfury]

An uncoupler is a chemical destroys the proton gradient by poking a hole in the membrane and so the protons from the inter membrane space leak back into the matrix. As a result, you should have less protons going into ATP synthase and thus less ATP. Is this correct logic and conclusion?

[CharonY]

Not all uncouplers are necessarily uncouplers of oxidative phosphorylation (it is a little bit context dependent). That being said, you should consider carefully what actually the driving force is (not the presence of protons alone, but something very specific about it). And look what goes where and why.

Edited March 4, 2013 by CharonY

[blazinfury]

Lets say I am discussing uncouplers of the electron transport chain, like aspirin. Wouldn't it destroy the proton gradient and in the process also decrease the amount of ATP produced?

[CharonY]

Correct. It is critical to point out that the proton-motive force is reduced rather than describing it in terms of having or more protons without point of reference. I.e. the relative difference is what matters.

[blazinfury]

Thank you very much for the clarification.

[BabcockHall]

I would not say that the membrane has a hole poked into it, exactly. As long as both the conjugate acid and the conjugate base forms of the uncoupler are soluble in the membrane, they should transport protons down their electrochemical gradient.

[blazinfury]

So are you saying that the effect is transient in terms of as long as the uncoupler is present it's effects will be felt but once it's gone the membrane will return to normal.

[BabcockHall]

I have never thought about it in those terms, but I suppose you are right.