Nicotinic dinucleotide

Ischaemia causes sustained elevation of free intracellular calcium ion concentration ([Ca ji), that can promote the conversion of xanthine dehydrogenase (EC 1.1.1.204) to xanthine oxidase (EC 1.1.3.22), i.e. the enzyme transfers electrons during the catalytic cycle of molecular oxygen instead of adenin-nicotin dinucleotides (McCord 1985). Under low energy conditions, where large parts of... 

The biological importance of these compounds stems from their use as cofactors. Both nicotinamide and nicotinic acid ate building blocks for coen2yme I (Co I), nicotinarnide—adenine dinucleotide (NAE)) (3) and coen2yme II (Co II), nicotinarnide—adenine dinucleotide phosphate (NAE)P) (4) (2). 

The result of this biosynthesis is that the product is nicotinic acid mononucleotide rather than free nicotinic acid. Ingested nicotinic acid is converted to nicotinic acid mononucleotide which, in turn, is converted to nicotinic acid adenine dinucleotide. Nicotinic acid adenine dinucleotide is then converted to nicotinamide adenine dinucleotide. If excess nicotinic acid is ingested, it is metabolized into a series of detoxification products (Fig. 4). Physiological metabohtes include /V-methylnicotinamide (19) and A/-methyl-6-pyridone-2-carboxamide (24) (1). 

N-Morpholino)propanesulfonic acid Relative molecular weight (dimensionless number) Nicotine amide adenine dinucleotide, oxidized form Nicotine amide adenine dinucleotide, reduced form Nuclear magnetic resonance... 

NADP can be converted to nicotinic acid adenine dinucleotide phosphate (NAADP), which has distinct functions in the regulation of intracellular calcium stores. The studies of these new roles of NAD(P) in metabolism are in their early stages, but they might soon help to better understand and explain the symptoms of niacin deficiency ( pellagra) [1]. 

In the first family, the metal is coordinated by one molecule of the pterin cofactor, while in the second, it is coordinated to two pterin molecules (both in the guanine dinucleotide form, with the two dinucleotides extending from the active site in opposite directions). Some enzymes also contain FejSj clusters (one or more), which do not seem to be directly linked to the Mo centers. The molybdenum hydroxylases invariably possess redox-active sites in addition to the molybdenum center and are found with two basic types of polypeptide architecture. The enzymes metabolizing quinoline-related compounds, and derivatives of nicotinic acid form a separate groups, in which each of the redox active centers are found in separate subunits. Those enzymes possessing flavin subunits are organized as a2jS2A2, with a pair of 2Fe-2S centers in the (3 subunit, the flavin in the (3 subunit, and the molybdenum in the y subunit. 

Brailoiu, E., Patel, S. and Dun, N. J. Modulation of spontaneous transmitter release from the frog neuromuscular junction by interacting intracellular Ca2+ stores critical role for nicotinic acid-adenine dinucleotide phosphate (NAADP). Biochem. J. 373 313-318, 2003. 

LEMS Lambert-Eaton myasthenic syndrome NAADP nicotinic acid-adenine dinucleotide phosphate... 

Yusufi ANK, Cheng J, Thompson MA, Chini EN, Grande JP 2001 Nicotinic acid-adenine dinucleotide phosphate (NAADP) elicits specific microsomal Ca2+ release from mammalian cells. Biochem J 353 531—536... 

In smooth muscle, just as in other cells, extracellular stimuli typically evoke an increase in cytosolic Ca2+ concentration ([Ca2+]c) by stimulating release of Ca2+ from intracellular stores or Ca2+ entry across the plasma membrane. Members of two closely related families of intracellular Ca2+ channels, ryanodine receptors and the receptors for inositol-1,4,5-trisphosphate (InsP3) appear to be expressed in all smooth muscle cells and they provide the most important route for release of Ca2+ from the sarcoplasmic reticulum (Sutko Airey 1996). The roles of additional Ca2+-mobilizing messengers, such as nicotinic acid adenine dinucleotide... 

Nicotinic acid derivatives occur in biologic materials as the free acid, as nicotinamide, and in two coenzymatic forms nicotinamide adenine dinucleotide (NAD), and nicotinamide adenine dinucleotide phosphate (NADP). These coenzymes act in series with flavoprotein enzymes and, like them, are hydrogen acceptors or, when reduced, donors. Several plants and bacteria use a metabolic pathway for the formation of nicotinic acid that is different from the tryptophan pathway used by animals and man (B39). 

Nicotine adenine dinucleotide phosphate (NADP+), 24 147 Nicotinic acid, 9 477-478 26 291 alkaloid precursor, 2 78 Ni-Cr alloys, 23 499. See also Nickel-chromium entries NiCrAlY coatings, 13 508 nido designation boranes, 4 184-186 boron hydrides, 4 170, 172-176 Nidrel, molecular formula and structure, 5 129t... 

The first biochemical analysis of a selenium-containing XDH was reported in 1999 by Andreesen s group. This preparation was specific for xanthine and did not hydroxylate nicotinic acid. Moreover, the enzyme contained FAD, acid-labile sulfur, iron, and a dinucleotide molybdenum cofactor. Most intriguing was the near-equimolar presence of tungsten and molybdenum. It should be noted that the culture medium contained nearly equimolar levels of these metals, making one wonder whether the specificity of this enzyme for metal may be relaxed (i.e., can use Mo or W). Selenium was also found in the preparation and could be released by treatment with cyanide indicating it was also a labile cofactor. This further confirmed the chemical nature of the cofactor from the NAH enzyme from the same strain. ... 

NAD, nicotine adenine dinucleotide A biochemical that functions as a cellular electron carrier. 

Although the structures for molecules having niacin activity are simple, the forms in which they act in human biochemistry are not so simple. Nicotinic acid and nicotinamide are precursors for three complex coenzymes in multiple oxida-tion/reduction (redox) reactions nicotinamide mononucleotide, NMN nicotinamide adenine dinucleotide, NAD+ and nicotinamide adenine dinucleotide phosphate, NADP. I shall use NAD+ as representative of the class. NADH is the corresponding reduced form. ... 

Formation of the 2-aminoadenine analogue of NAD by H.Ep.-2 cells in culture has been demonstrated, and it appears quite likely that dinucleotides containing 2-aminoadenine and nicotinic acid or nicotinamide can be formed in living... 

Nicotinate and nicotinamide, together referred to as niacin, are required for biosynthesis of the coenzymes nicotinamide adenine dinucleotide (NAD"") and nicotinamide adenine dinucleotide phosphate (NADP" ). These both serve in energy and nutrient metabolism as carriers of hydride ions (see pp. 32, 104). The animal organism is able to convert tryptophan into nicotinate, but only with a poor yield. Vitamin deficiency therefore only occurs when nicotinate, nicotinamide, and tryptophan are all simultaneously are lacking in the diet. It manifests in the form of skin damage (pellagra), digestive disturbances, and depression. 

On NMR monitoring of the reaction of nicotine adenine dinucleotide (NAD ), an important co-factor in enzymatic reactions, with 43 at pH 6, the formation of two unique diastereomeric cyclic trimeric metallacalixarene systems 49, in a self-assembly mode, was evident (1999JOM(589)66). These products have a narrow stability range at pH 6 and decompose at lower or higher pH. The complex 49 was neither electroactive nor it was possible to convert it to the corresponding NADH-based system (1999JOM(589)66). 

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