Question

How does the level ATP and NADH affect glycolysis and TCA cycle?

I know the high levels of ATP will slow down glycolysis, and that low ATP levels will activate it. But does NADH inhibit glycolysis too?

Also, how do ATP/NADH levels affect the TCA cycle?

Thank you!

Answer 1

Glycolysis is a metabolic pathway and an anaerobic source of energy that has evolved in nearly all types of organisms. The process entails the oxidation of glucose molecules, the single most important organic fuel in plants, mirobes, and animals. Most cells prefer glucose (there are exceptions, such as acetic acid bacteria which prefer ethanol). In glycolysis, per molecule of glucose, 2 ATP molecules are utilized, while 4 ATP, 2 NADH, and 2 pyruvates are produced. The pyruvate can be used in the citric acid cycle, or serve as a precursor for other reactions.

High NADH inhibits glycolysis as well by feedback inhibition.

When adequate ATP and NADH levels are available, the rates of these reactions decrease. When more ATP is needed, as reflected in rising ADP levels, the rate increases. α-Ketoglutarate dehydrogenase will also be affected by the levels of succinyl CoA, a subsequent intermediate in the cycle, causing a decrease in activity.