NADPH Nicotinamide adenine dinucleotide phosphate

NADP = nicotinamide-adenine dinucleotide phosphate NADPH = reduced nicotinamide—adenine dinucleotide phosphate NDP = nucleoside... 

NAD" — see Nicotinamide adenine dinucleotide NADP" — see Nicotinamide adenine dinucleotide phosphate NADPH... 

The first step in the biological degradation of lysine is reductive animation with a-ketoglutarate to give saccharopine. Nicotinamide adenine dinucleotide phosphate (NADPH), a relative of NADH, is the reducing agent. Show the mechanism. 

All NOS isoforms utilize L-arginine as the substrate, and molecular oxygen and reduced nicotinamide adenine dinucleotide phosphate (NADPH) as cosubstrates. Flavin adenine dinucleotide (FMN), flavin mononucleotide (FAD), and (6R)-5,6,7,8-tetrahydro-L-biopterin (BH4) are cofactors of the enzyme. All NOS isoforms contain heme and bind calmodulin. In nNOS and eNOS,... 

Ethanol is oxidized by alcohol dehydrogenase (in the presence of nicotinamide adenine dinucleotide [NAD]) or the microsomal ethanol oxidizing system (MEOS) (in the presence of reduced nicotinamide adenine dinucleotide phosphate [NADPH]). Acetaldehyde, the first product in ethanol oxidation, is metabolized to acetic acid by aldehyde dehydrogenase in the presence of NAD. Acetic acid is broken down through the citric acid cycle to carbon dioxide (CO2) and water (H2O). Impairment of the metabolism of acetaldehyde to acetic acid is the major mechanism of action of disulfiram for the treatment of alcoholism. 

The most important product of the hexose monophosphate pathway is reduced nicotinamide-adenine dinucleotide phosphate (NADPH). Another important function of this pathway is to provide ribose for nucleic acid synthesis. In the red blood cell, NADPH is a major reducing agent and serves as a cofactor in the reduction of oxidized glutathione, thereby protecting the cell against oxidative attack. In the syndromes associated with dysfunction of the hexose monophosphate pathway and glutathione metabolism and synthesis, oxidative denaturation of hemoglobin is the major contributor to the hemolytic process. 

It is helpful to think of the photosynthesis reaction as the sum of an oxidation half reaction and a reduction half reaction as shown in Figure 1. In fact, nature does separate these half reactions, in that the reduction of C02 to carbohydrates occurs in the stroma of the chloroplast, the organelle in the leaf where the photosynthesis reaction occurs, - whereas, the light-driven oxidation half reaction takes place on the thylakoid membranes which make up the grana stacks within the chloroplast. Reduced nicotinamide adenine dinucleotide phosphate (NADPH) carries the reducing power and most of the energy to the stroma to drive the fixation of C02 with the help of some additional energy provided... 

DHFR catalyses the hydride-ion transfer between the nicotinamide adenine dinucleotide phosphate (NADPH) cofactor and a substrate molecule (S) according to... 

Hexachloroethane is metabolized by the mixed function oxidase system by way of a two-step reduction reaction involving cytochrome P-450 and either reduced nicotinamide adenine dinucleotide phosphate (NADPH) or cytochrome b5 as an electron donor. The first step of the reduction reaction results in the formation of the pentachloroethyl free radical. In the second step, tetrachloroethene is formed as the primary metabolite. Two chloride ions are released. Pentachloroethane is a minor metabolic product that is generated from the pentachloroethyl free radical. 

Two important implications of the reactions described in Equations (5.1) and (5.2) are (i) that redox reactions play an important role in metabolic transformations, with the cofactors nicotinamide adenine dinucleotide (NAD+) acting as electron acceptor in catabolic pathways and nicotinamide adenine dinucleotide phosphate (NADPH) as electron donor in anabolism, and (ii) that energy must be produced by catabolism and used in biosyntheses (almost always in the form of adenosine triphosphate, ATP). 

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. 

The term NOS is used to denote a family of three related but distinct isoenzymes neuronal NOS (nNOS) endothelial NOS (eNOS, endothelium and platelets) and inducible NOS (iNOS, endothelium, vascular smooth muscle and macrophage). In addition to reduced nicotinamide adenine dinucleotide phosphate (NADPH) shown in Figure 5.5, NOS enzymes also require flavin adenine dinucleotide (FAD), flavin mononucleotide (FMN) and tetrahydrobiopterin (BH4) as coenzymes. 

By means of this reaction, the use of the costly and unstable natural redox cofactor reduced nicotinamide adenine dinucleotide phosphate (NADPH) was circumvented and the reactions were carried out in a straightforward procedure in a chemical laboratory (Scheme 10.2, Table 10.1). 

The nicotinamide coenzymes nicotinamide adenine dinucleotide (NADH) and nicotinamide adenine dinucleotide phosphate (NADPH) are associated with a wide variety of enzymes involved in oxidation-reduction reactions (Fig. 21). NADH is typically involved in oxidative catabolic reactions, while NADPH is primarily used in biosynthetic pathways [58]. 

In view of the oxidant nature of ozone, a number of investigators have evaluated its effects on intracellular compounds that are normally active in cellular redox reactions. Attention has focused particularly on reduced pyridine nucleotides—reduced nicotinamide adenine dinudeotide (NADH) and reduced nicotinamide adenine dinucleotide phosphate (NADPH)— and on sulfhydryl compounds, specifically reduced glutathione (GSH). 

T2. Temple, A. R., George, D. J., and Done, A. K., Reduced nicotinamide-adenine dinucleotide phosphate (NADPH) enhancement of p-nitrophenol glucuronidation. Biochem. Pharmacol. 20, 1718-1720 (1971). 

Nicotinamide adenine dinucleotide phosphate (NADPH), 610, 643, 659 Niobium(V) complexes... 

Mitomycin (mitomycin C, Mitocin-C, Mutamycin) is an antibiotic that is derived from a species of Streptomyces. It is sometimes classified as an alkylating agent because it can covalently bind to and cross-link DNA. Mitomycin is thought to inhibit DNA synthesis through its abihty to alkylate double-strand DNA and bring about interstrand cross-hnking. There is evidence that enzymatic reduction by a reduced nicotinamide-adenine dinucleotide phosphate (NADPH) dependent reductase is necessary to activate the drug. 

I I 3. The answer is c. (Hardman, pp 1243-1247.) Antimetabolites of folic acid such as methotrexate, which is an important cancer chemotherapeutic agent, exert their effect by inhibiting the catalytic activity of the enzyme dihydrofolate reductase. The enzyme functions to keep folic acid in a reduced state. The first step in the reaction is the reduction of folic acid to 7,8-dihydrofolic acid (FH2), which requires the cofactor nicotinamide adenine dinucleotide phosphate (NADPH). The second step is the conversion of FH2 to 5,6,7,8-tetrahydrofolic acid (FH ). This part of the reduction reaction requires nicotinamide adenine dinucleotide (NADH) or NADPH. The reduced forms of folic acid are involved in one-carbon transfer reactions that are required during the synthesis of purines and pyrimidine thymidylate. The affinity of methotrexate for dihydrofolate reductase is much greater than for the substrates of folic acid and FH2. The action of... 

Working at 3.0T with proton decoupling, Sevastianova et al. partially resolved the resonance of nicotinamide adenine dinucleotide phosphate (NADPH) from that of a-NTP. ° NADPH was higher in subjects with nonalcoholic steatohepatitis and cirrhosis than in healthy controls and correlated with disease severity. Solga et al. investigated the reliability of both and P MRS at 1.5 T in cohorts of obese diabetic subjects and healthy con-trols. ° Whereas hepatic fat could be reliably measured with relative ease, hepatic ATP proved difficult with obese subjects due to reduced P SNR. 

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