Nicotinic acid, nicotinamide

Niacin (nicotinic acid) Nicotinamide adenine dinncleotide (NAD )... 

The structures of pyridine, nicotinic acid, nicotinamide, and nicotine. 

Niacin Nicotinic acid, nicotinamide Coenzyme in oxidation and reduction reactions, functional part of NAD and NADP Pellagra—photosensitive dermatitis, depressive psychosis... 

Recently nicotinic acid has been found to lower serum cholesterol in hypercholesteremia, and also in normal persons and rabbits (A3, F2). It was shown that the hypercholesteremia, induced by a 48-hour fast, could be completely corrected by giving the animals large doses of nicotinic acid during the fast. In contrast to nicotinic acid, nicotinamide does not lower the cholesterol level (M10). Several explanations are offered for the action of nicotinic acid (1) it inhibits cholesterol biosynthesis, (2) it interferes with coenzyme A, and (3) it involves a hitherto unknown pharmacologic effect. The renewed clinical interest in nicotinic acid induced us to look for a more specific and sensitive assay for nicotinic acid (B7, M8). 

B3 Nicotinic acid Cereal, light meat, beef, tuna peanuts beans from nicotinic acid, nicotinamide is formed in the bver <1 yr 2 NE 1-13 yr from 4 to 11 NE >13 yr man 17 NE >13 yr woman 13 NE pregnancy 18 NE lactating women 17 NE... 

Niacin Nicotinic acid Nicotinamide NAD", NADP" Electron transfer... 

Niacin (nicotinic acid, nicotinamide) has the active forms NAD and NADPH. It functions in electron transfer. A deficiency of niacin causes pellagra, which is characterized by der matitis, diarrhea, and dementia. There is no known toxicity for this vitamin. High doses of niacin are used to treat hyperlipidemia. 

The physiologically active forms of niacin are nicotinic acid, nicotinamide, and their coenzymes (93,96). Niacytin and the niacynogens appear to have limited bioavailability, although more work is needed in this area. The absorption and metabolism of niacin has been reviewed (20,93). 

The availability of commercial bench-top mass spectrometry detectors for HPLC is facilitating the development of HPLC-MS methods for many analytes. This is more common in pharmaceutical than food applications. As is generally the case, mass spectrometry is first being applied to standard solutions and relatively simple samples before being applied to more complex food matrices. A standard mixture of ten vitamers, AA, DHAA, PN, PL, PM, thiamine, nicotinic acid, nicotinamide, pantothenic acid and biotin, were recently determined by HPLC-particle beam... 

Figure 8.3. Metabolites of nicotinamide and nicotinic acid. Nicotinamide deamidase (nicotinamidase), EC 3.5.1.19 nicotinamide Af-methyltransferase, EC 2.1.1.1 aldehyde dehydrogenase, EC 1.1.1.1. Relative molecular masses (Mr) nicotinamide, 123.1 nicotinic acid, 122.1 nicotinamide JV-oxide, 139.1 Af -methyl nicotinamide, 139.1 trigonelline, 137.1 nicotinuric acid, 179.2 and methyl pyridone carboxamides, 154.1.

Animals and yeasts can synthesize nicotinamide from tryptophan via hydroxyanthranilic acid (52) and quinolinic acid (53, Fig. 6A) (31), but the biosynthetic capacity of humans is limited. On a diet that is low in tryptophan, the combined contributions of endogenous synthesis and nutritional supply of precursors, such as nicotinic acid, nicotinamide, and nicotinamide riboside, may be insufficient, which results in cutaneous manifestation of niacin deficiency under the clinical picture of pellagra. Exogenous supply of nicotinamide riboside was shown to promote NAD+-dependent Sir2-function and to extend life-span in yeast without calorie restriction (32). 

F-9) (1-7) Niacin (=nicotinic acid). Nicotinamide is a related amide compound with similar activity as niacin ... 

Niacin (nicotinic acid, nicotinamide) (B ) is an essential part of codehydrogenases 1 and II, cmd so it is present in every living cell. It is used in some hyperlipidaemias, see page 527. 

Synonyms Vitamin B3, Nicotinic acid Nicotinamide Pellagra-preventative factor 3-Car-boxypyridine... 

These compounds are derived from the vitamin niacin (nicotinic acid, nicotinamide) and require it for their synthesis. Small amounts of niacin are derived from the essential amino acid tryptophan. 

After the antibodies have demonstrated acceptable sensitivity, one should proceed to testing for specificity (cross-reactivity) with structurally similar compounds or compounds that are most likely to be present in the assay matrix. The assay specificity was determined by running the cotinine assay in the presence of compounds structurally similar to cotinine or likely to be present in human samples. Examples included caffeine, nicotinic acid, nicotinamide, and aspirin. Protocol (Number 4) provides testing for assay specificity with the following steps ... 

Prepare samples with 10,000 ng/mL of each individual compounds caffeine, nicotinic acid, nicotinamide, and aspirin (rrrNote 14). 

USE As a reagent for the detection and determination of nicotinic acid, nicotinamide, and other pyridine compds. Caution May cause dermatitis of both primary and allergic types. 

The order of their effectiveness as photosensitizers for the oxidation of glycyltryptophan in aqueous solution is nicotinic acid > nicotinamide > nicotine-hydroxymethylamide these reactions seems to involve the superoxide radical anion. 

Supplements. Niacin supplements are available as nicotinamide or nicotinic acid. Nicotinamide is the form of niacin typically used in nutritional supplements and in food fortification. Nicotinic acid is available over the counter and with a prescription as a cholesterol-lowering agent. ... 

BiosytMesis In animals tryptophan - kynutenine - 3-hydroxyanthranilic acid - quinolinic acid (pyri-dine-2,3-dicaiboxylic acid) - nicotinic acid - nicotinamide. In bacteria and higher plants from L- aspar-tic acid and a C3-unit, probably D-glyceraldehyde 3-phosphate. Also by cleavage of NAD. 

Vitamin B3 Vitamin B3 (niacin) has different physiologically active forms, nicotinic acid, nicotinamide, and their coenzymes, which are very stable at ambient temperature. Usually acid or alkaline hydrolysis are used to convert nicotinamide to nicotinic acid for quantitation of both vitamers as nicotinic acid the first treatment (acid) is used to quantitate biologically available niacin, while alkaline hydrolysis provides an estimate of the total niacin content. Nicotinic acid has been analyzed using ion exchange or RP chromatography with amino columns. Detection is performed with UV absorbance at 254 nm. 

Nomenclature. Niacin (vitamin PP) group name for nicotinic acid, nicotinamide, NAD, and NADP. 

The UPLC-MS/MS method has also been developed for fast simultaneous separation and determination of 14 different water-soluble vitamins and vitamin-like compounds in infant formula (thiamine, riboflavin, pantothenic acid, nicotinic acid, nicotinamide, pyridoxine, pyridoxal, biotin, fohc acid, cyanocobalamin, ascorbic acid, L-camitine, choline, and taurine) [91], Methotrexate was also used as an internal standard for riboflavin, cyanocobalamin, biotin, and folic acid, while nicotinamide was used as an internal standard for the other compounds. 

Nicotinic acid, nicotinamide, inosine monophosphate, adenosine 5 -monopho-sphate (AMP), adenosine 5 -diphosphate (ADP) and adenosine 5 -triphosphate (ATP) were extracted from red blood cells and baseline resolved on a C g column (A = 280 nm or 254 nm) using a complex 22-min 4/96 -> 30/70 methanol/water (100 mM KH2PO4 with 8mM tributylamine at pH 5.5) gradient Peak shapes were excellent [448]. 

Niacin, also known as vitamin B3, nicotinic acid or vitamin PP, is a water-soluble B-complex vitamin (Table 7.1). This vitamin is the generic descriptor for two vitamers niacin and niacinamide. In the research literature the terms nicotinic acid/nicotinamide are most commonly used, while in medical practice niacin/niadnamide are preferred. The vitamin is obtained from the diet in the form of nicotinic acid, nicotinamide and tryptophan, which are transformed to nicotinamide adenine dinucleotides, NAD and NADP. These compounds participate in cellular oxidation-reduction reactions that are critical for energy production. NAD and NADP also participate in a wide variety of... 

The vitamin is obtained from the diet in the form of nicotinic acid, nicotinamide, NAD/NADP and tryptophan. The Recommended Dietary Allowance (RDA) for adults is 16mg/day of niacin equivalents for men and 14mg/day for women (Food and Nutrition Board 1998). 

The vitamin is obtained from the diet in the form of nicotinic acid, nicotinamide and tryptophan. 

A mixture of nicotinic acid, nicotinamide, trigonelline and tryptophan can be separated chromatographicaUy, using as solvent a 5 i mixture of n-butanol and concentrated hydrochloric acid, saturated with water. Tryptophan is revealed by ninhydrin, while nicotinic acid, nicotinamide and trigonelline are detected with phosphomolybdic acid reagent and the color developed with stannous chloride, which reduces the phosphomolybdic acid to give a blue spot. The Rf values for the butanol-HCl solvent are nicotinic acid, 0.37 nicotinamide, 0.28 trigonelline, 0.38 and tryptophan, 0.62. 

Analysis of nicotinic acid, nicotinamide, and its metabolites in biological materials, i.e., blood, plasma, urine, and tissues, is important in studies on biochemical pathways (Hengen and deVries, 1985). Finder et al. (1971) described several paper and thin-layer chromatographic systems useful for the differentiation of nucleotides in tissues derived from nicotinamide and nicotinic acid. Hengen and deVries (1985) provided a table summarizing the Rp values of nicotinic acid, nicotinamide, and various intermediates of NAD+ and NADP-I- synthesis for both paper and thin-layer chromatography. Haworth and Walmsley (1972) used two-dimensional TLC on silica gel for the identification of tryptophan metabolites in urine and resolved 32 compounds including nicotinic acid and nicotinamide. Kala et al. (1978) used silica gel TLC to examine urine for nicotinic acid and its metabolites after administration of nicotinyl alcohol. They... 

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