Riboflavin 5-phosphate

Riboflavin-5 -Phosphate. Riboflavin-5 -phosphate [146-17-8] (vitamin B2 phosphate, flavin mononucleotide, FMN, cytoflav), C2yH22N402P,... 

Riboflavin, riboflavin-5 -phosphate (Na salt, 2H2O) and ribonucleic acid see entries in Chapter 6. 

Riboflavin, or vitamin B2, is a constituent and precursor of both riboflavin 5 -phosphate, also known as flavin mononucleotide (FMN), and flavin adenine dinucleotide (FAD). The name riboflavin is a synthesis of the names for the molecule s component parts, ribitol and flavin. The structures of riboflavin. 

Riboflavin was first isolated from whey in 1879 by Blyth, and the structure was determined by Kuhn and coworkers in 1933. For the structure determination, this group isolated 30 mg of pure riboflavin from the whites of about 10,000 eggs. The discovery of the actions of riboflavin in biological systems arose from the work of Otto Warburg in Germany and Hugo Theorell in Sweden, both of whom identified yellow substances bound to a yeast enzyme involved in the oxidation of pyridine nucleotides. Theorell showed that riboflavin 5 -phosphate was the source of the yellow color in this old yellow enzyme. By 1938, Warburg had identified FAD, the second common form of riboflavin, as the coenzyme in D-amino acid oxidase, another yellow protein. Riboflavin deficiencies are not at all common. Humans require only about 2 mg per day, and the vitamin is prevalent in many foods. This vitamin... 

Thiobacillus ferrooxidans function. 6, 651 Rhus vernicifera stellacyanin structure, 6,651 Riboflavin 5 -phosphate zinc complexes, 5,958 Ribonucleotide reductases cobalt, 6,642 iron, 6,634... 

Riboflavin (ii) riboflavin-5-phosphate E 101 Yes Semisynthetic, obtained from bacterial fermentation (Btakeslea O Q ... 

Blanc, V. Lagneaux, D. Dider, P., et al., Cloning and analysis of structural genes from streptomyces pristinaspirales encoding enzymes involved in the conversion of pristinamycin PUB to PIIA PIIA synthase and NADH riboflavin 5 phosphate oxidoreductase. 1995, 177, 5206-5214. 

Riboflavin-5-phosphate (ElOla). This material is both less bitter and more water stable than riboflavin. It is normally only encountered as a pure synthetic substance. Like riboflavin it is used on panned products. 

The alcoholysis of the cyclic phosphate of catechol by alditols can lead, after acid hydrolysis of intermediate, cyclic phosphates, to the selective formation of phosphoric esters of the primary hydroxyl groups in the alditols. Thus, erythritol and D-mannitol afford, after chromatographic purification of the reaction products, their 1-phosphates in yields of 31 and 38%, respectively.217 The method was used to convert riboflavine into riboflavine 5 -phosphate.218 1-Deoxy-1-fluoro-L-glycerol has been converted into the 3-(dibenzyl phosphate) in 54% yield by selective reaction with dibenzyl phosphorochloridate. 219... 

So what does riboflavin do As such riboflavin does nothing. Like thiamine, riboflavin must undergo metabolic change to become effective as a coenzyme. It fact, it undergoes two reactions. The first converts riboflavin to riboflavin-5-phosphate (commonly known as flavin adenine mononucleotide, FMN), about which we will say no more, and the second converts it to flavin adenine dinucleotide, FAD. The flavins are a class of redox agents of very general importance in biochemistry. FAD is the oxidized form and FADH2 is the reduced form. ... 

Karappuchamy etal. [164] have described cathodic electrodeposition of porous ZnO thin film modified with the dye in an aqueous solution of zinc nitrate and riboflavin 5 -phosphate. 

Add with stirring parabens, niacinamide, and riboflavin 5 phosphate sodium. Rinse the container with 5 mL water. Stir well. Mix until in solution. 

They were found not to react with BESOD, the rate constant was estimated to be < 10 M s , if there was a reaction at all The reaction of BESOD was also investigated with several other radicals generated by pulse radiolysis. With the semiquinone of riboflavin 5 -phosphate no reaction was detected. The semiquinone of 9,10-anthraquinone-2-sulfonate and the radical anion of 4-nitroacetophenone converted the enzyme into an unreactive form... 

Riboflavin (vitamin B2) 6,7-dimethyl-9-(D-l-ribityl)isoalloxazine (63), was discovered as a coloring matter in milk in 1879, but its importance was not then realized. Deficiency causes lesions of the eye and of the angle of the mouth. Riboflavin is phosphorylated by adenosine triphosphate (ATP) to give riboflavin 5 -phosphate (flavinadenine mononucleotide, FMN) and then flavinadenine dinucleotide (FAD) (64 R = riboflavin). These function as prosthetic groups in a number of flavoproteins which are dehydrogenation catalysts by virtue of the oxidation-reduction properties of the isoalloxazine system. 

The attention of biochemists was first attracted to flavins as a result of their color and fluorescence. The study of spectral properties of flavins (Fig. 15-8) has been of importance in understanding these coenzymes. The biochemical role of the flavin coenzymes was first recognized through studies of the "old yellow enzyme"144 145 which was shown by Theorell to contain riboflavin 5 -phosphate. By 1938, FAD was recognized as the coenzyme of a different yellow protein, D-amino acid oxidase of kidney tissue. Like the pyridine nucleotides, the new flavin coenzymes were reduced by dithionite to nearly colorless dihydro forms (Figs. 15-7 and 15-8) revealing the chemical basis for their function as hydrogen carriers. 

Mitochondrial succinate dehydrogenase, which catalyzes the reaction of Eq. 15-21, contains a flavin prosthetic group that is covalently attached to a histidine side chain. This modified FAD was isolated and identified as 8a-(Ne2-histidyl)-FAD 219 The same prosthetic group has also been found in several other dehydrogenases.220 It was the first identified member of a series of modified FAD or riboflavin 5 -phosphate derivatives that are attached by covalent bonds to the active sites of more than 20 different enzymes.219... 

These include 8a-(Ne2-histidyl)-FMN,221 8a-(N81-histidyl)-FA D,222 8a-(0-tyrosyl-FAD),223 and 6-(S-cysteinyl)-riboflavin 5 -phosphate, which is found in trimethylamine dehydrogenase (Fig. 15-9).224 An 8-hydroxy analog of FAD (-OH in place of the 8-CH3)... 

Luminescent bacteria all appear to obtain light from a riboflavin-5 -phosphate dependent oxygenase, which converts a long-chain aldehyde (usually n-tetradecanal) to a carboxylic acid (Eq. 23-47). Here FH2 is the riboflavin 5 -P, which is thought to be supplied by a flavin reductase.6793... 

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