Question

If the proton ATPase of the mitochondrion is inhibited by blocking proton movement through ATP synthase. In a respiring cell, will there be an increase in heat production, lowered proton pumping, and build up of NADH?

Answer 1

The ATP synthase works by allowing the protons to move through the complex and produce ATP. The ATP synthase can be inhitbited by blocking the movement of the protons by the help of various inhibitors. Blocking of proton movement through the complex would inhibit the functioning of the ATP synthase and thus there will be no formation of ATP. Due to the damage in the ATP synthase and no formation of ATP, the entire electron transport chain(ETC) is damaged and inhibited. This is because both the ETC and ATP production are a coupled process. With no formation of ATP, there will be no consumption of Oxygen and thus the ETC shuts down resulting in buildup of NADH. This inhibits gluconeogenesis in turn causing lactate to accumulate in the muscle cells. There will leakage of the protons hence the protons will not be pumped in a regulated and controlled manner that will lead to decrease in proton pumping due to non functional ETC. But because the ATP won't be produced anymore due to inhibiton, there will not be increased heat production from the body as the heat is released only due to ATP hydrolysis.