AP BIOLOGY

Detailed explanation-1: -Once the glycolytic end-product pyruvate is transported into mitochondria, the pyruvate dehydrogenase (PDH) complex decarboxylates it into acetyl-CoA and simultaneously reduces NAD+ to NADH (87).

Detailed explanation-2: -Oxidoreductase binding of NAD However, these enzymes are also referred to as dehydrogenases or reductases, with NADH-ubiquinone oxidoreductase commonly being called NADH dehydrogenase or sometimes coenzyme Q reductase. There are many different superfamilies of enzymes that bind NAD+ / NADH.

Detailed explanation-3: -The enzymes using NAD+ in hydride-transfer are known as dehydrogenases or oxidoreductases, which catalyze reduction of NAD+ into NADH (Examples shown in Figure 1).

Detailed explanation-4: -A dehydrogenase is an enzyme belonging to the group of oxidoreductases that oxidizes a substrate by reducing an electron acceptor, usually NAD+/NADP+ or a flavin coenzyme such as FAD or FMN.

Detailed explanation-5: -Complex I (NADH dehydrogenase) is the first enzyme in the respiratory chain. It catalyses the electron transfer from NADH to ubiquinone that is associated with proton pumping out of the matrix.