Can protein somehow enter TCA cycle? How does protein gain entry into TCA cycle to generate energy?
Proteins, carbohydrates and fat all enter the TCA cycle at one point or another, since they are all macromolecules. There are various kinds of proteins, each of which must enter the pathway at different times. The main problem with proteins is the nitrogen they contain, which is toxic to the body by itself. It must be removed and excreted in the urine. The rest of the protein is broken down into an organic acid, which enters the Krebs cycle. Just like pyruvate, it can reduce NAD+ to NADH, which is the main source of ATP generation.
