AP BIOLOGY

Detailed explanation-1: -Additionally, glutamate dehydrogenase, a central enzyme involved in -ketoglutarate formation from glutamate, 34 can also make NADH from NAD+. Under hyperglycemic conditions, both the glycolytic pathway and the Krebs cycle can be intensively fluxed by glucose.

Detailed explanation-2: -NAD+ can be reduced to NADH via dehydrogenases and can also be phosphorylated to NADP+ via NAD+ kinases (NADKs). The NAD+/NADH redox couple is known as a regulator of cellular energy metabolism, that is, of glycolysis and mitochondrial oxidative phosphorylation.

Detailed explanation-3: -NADH dehydrogenase is an enzyme that converts nicotinamide adenine dinucleotide (NAD) from its reduced form (NADH) to its oxidized form (NAD+). Members of the NADH dehydrogenase family and analogues are commonly systematically named using the format NADH:acceptor oxidoreductase.

Detailed explanation-4: -Initially, the intracellular nicotinamide phosphoribosyltransferase (iNAMPT) recycles NAM into nicotinamide mononucleotide (NMN), which is then converted into NAD+ via the different NMNATs. NAM can be alternatively methylated by the enzyme nicotinamide N-methyltransferase (NNMT) and secreted via the urine.

Detailed explanation-5: -The first enzyme utilizing NAD+ in glycolysis is glyceraldehyde 3-phosphate dehydrogenase [22].