Nicotinamide adenine dinucleotide storage

For the formation of one 02 molecule four electrons have to be transferred. This requires a "quantum storage device". In the photosynthetic system of green plants this is achieved with two photosystems that are linked through an electron transport chain, Fig. 10.2, and by means of the thylakoid-membrane that enables the separation of the photoproducts 02 and the reduced form of nicotinamide adenine dinucleotide phosphate, NADPH. 

In the first stage of respiration, a six-carbon glucose molecule is split into a pair of three-carbon molecules. Hydrogen Ions and electrons also are produced in glycolysis. These combine with electron carrier ions called nicotinamide adenine dinucleotide (NAD+) to form NADH. NADH is a coenzyme that is made from vitamin B4, which is also called niacin or nicotinic acid. ATP and NADH serve as temporary storage sites for energy and electrons, respectively, during respiration. Two molecules of ATP are used, and four molecules are produced. ... 

Also known as iditol dehydrogenase, this enzyme catalyzes the interconversion of sorhitol to fructose in the presence of the coenzyme nicotinamide adenine dinucleotide. The enzyme is cytosolic, with the highest tissue concentration in the liver and a short half-life of less than a few hours. The plasma enzyme is relatively unstable and activity can he rapidly lost when serum is stored at room temperature storage at lower temperatures reduces the deactivation of the enzyme. The enzyme measurement can he useful in canine, nonhuman primate, and rat studies as a conhrmatory test for hepatotoxicity (Dooley, Turnquist, and Racich 1979 Pakuts, Whitehouse, and Paul 1988 Blazka et al. 1996 Travlos et al. 1996). However, the changes in liver injury are often relatively small compared to baseline values. 

Reece, P. 1985. The fate of nicotinamide adenine dinucleotide in minced flesh of cod (Gadus morhua) and its association with formaldehyde production during frozen storage. Sci. Tech Froid. 4 375-79. 

ATP, ADP, and AMP are agents for the storage and transfer of phosphate groups. Nicotinamide adenine dinucleotide (NAD ) and flavin adenine dinucleotide (FAD) are agents for the storage and transport of electrons in metabolic oxidations and reductions. NAD is a two-electron oxidizing agent... 

Lipid oxidation in subcellular fractions can be mediated by enzyme systems in muscle microsomes that maintain iron in the ferrous form by reduced nicotinamide adenine dinucleotide (NADH). However, this redox system may not be enzymatic because, unlike lipoxygenase, no specific lipid oxidation products have been identified. Ascorbate and other reducing agents may have the same effects in the presence of heme-protein complexes. On the other hand, the presence of 15-lipoxygenase in chicken muscle may be responsible for oxidative deteriorations in uncooked chicken meat during frozen storage. Phospholipases... 

Several microorganisms are known to accumulate PHB within the cells as an intracellular storage material for carbon and energy source. In microbes PHB synthesis takes place by a sequence of reactions catalyzed by three enzymes— 3-ketothiolase, acetoacetyl-coA reductase and PHB synthase. The first step is catalyzed by the enzyme 3-ketothiolase (E.C. 2.3.1.16) which condenses acetyl-CoA to acetoacetyl-CoA. This intermediate is reduced to D (-)-P-hydroxybutyryl-CoA by an Nicotinamide Adenine Dinucleotide Phosphate (NADPH)-dependent acetoacetyl-CoA reductase (E.C.1.1.1.36) and the enzyme PHB synthase catalyzes the head to tail polymerization of the monomer to PHB (Figure 17.3). 

---