Biochemistry of Riboflavin

Kulinski, T., Visser, A. J. W. G., O Kane, D. J., and Lee, J. (1987). Spectroscopic investigations of the single tryptophan residue and of riboflavin and 7-oxolumazine bound to lumazine apoprotein from Photobacterium leiognathi. Biochemistry 26 540-549. 

The coenzymes, FMN and FAD, are the physiologically active vitamers. The biochemistry, absorption, metabolism, and physiological functions of riboflavin have been reviewed (80,81). 

Absorption and Metabolism of Thiamin Biochemistry of Huamin Thiamin Deficiency Assessment of Thi in Status Determination of tite Thiamin Requiremoit Use of Thiamin in Maple Syrup Urine Disease Riboflavin... 

Riboflavin, physiology and biochemistry of formation 84PHA805. Tocopherol, chemistry and natural occurrence of 81KPS263. Tocopherol, structure and functions of 86ACR194. 

Figure 3.8. Structures of vitamins or vitamin-derived molecules that function in oxidation-reduction reactions. The oxidation of these redox groups in the inner mitochondricil membrane contributes to the electron transport chain that carries electrons from the oxidation of glucose to oxygen and in the process pumps protons from one side to the other of the inner mitochondrial membrane (see Chapter 8 for details). The proton gradient thus formed is used to phosphorylate ADP to form 32 of the 36 ATPs resulting from the oxidation of one glucose molecule to six CO2 and six H2O molecules. A Vitamin B3, also called niacin or nicotinic acid, becomes converted to the amide (nicotinamide) and dressed up with a ribose sugar. Then, in a manner like that of riboflavin in B becomes phosphorylated to form nicotinamide mononucleotide (NMN) or further reacted with the addition of adenosine monophosphate (AMP) to form nicotinamide adenine dinucleotide (NAD). B Vitamin B2, also known as riboflavin, is shown converted to the forms involved in redox reactions such as those of the electron transport chain. (From Biochemistry, Second Edition, D. Voet and J. Voet, Copyright 1995, John Wiley Sons, New York. Reprinted with permission of John Wiley Sons, Inc.)...

Coverage includes B vitamins and folate in the context of a historical background, disease, cardiovascular effects and the importance of vitamins in biochemistry as illustrated by a single vitamin. Thereafter there are chapters on the chemistry and biochemistry of thiamine, riboflavin, niacin, pantothenic acid, pyridoxine, biotin, folate and cobalamin. Methodical aspects include characterization and assays of B vitamins and folate in foods of all kinds, dietary supplements, biological fluids and tissues. The techniques cover solid-phase extraction, spectrofluorimetry, mass spectrometry, HPLC, enzymatic assay, biosensor and chemiluminescence. In terms of fimction and effects or... 

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. ... 

Bates CJ (1987) Human riboflavin requirements, and metabolic consequences of deficiency in man and animals. World Review of Nutrition and Dietetics 50,215-65. Ghisla S and Massey V (1989) Mechanisms of flavoprotein-catalyzed reactions. European Journal of Biochemistry ISl, 1-17. 

The chemistry of the cofactors has provided a fertile area of overlap between organic chemistry and biochemistry, and the organic chemistry of the cofactors is now a thoroughly studied area. In contrast, the chemistry of cofactor biosynthesis is stiU relatively underdeveloped. In this review the biosynthesis of nicotinamide adenine dinucleotide, riboflavin, folate, molyb-dopterin, thiamin, biotin, Upoic acid, pantothenic acid, coenzyme A, S-adenosylmethionine, pyridoxal phosphate, ubiquinone and menaquinone in E. coli will be described with a focus on unsolved mechanistic problems. 

Almost all the activated carriers that act as coenzymes are derived from xnta-mins. Vitamins are organic molecules that are needed in small amounts in the diets of some higher animals. Table 15.3 lists the vitamins that act as coenzymes (Figure 15.17). This series of vitamins is known as the vitamin B group. Note that, in all cases, the vitamin must be modified before it can serve its function. We have already touched on the roles of niacin, riboflavin, and pantothenate. We will see these three and the other B vitamins many times in our study of biochemistry. 

Weatherby, G. D., and D. O. Carr Riboflavin-Catalyzed Photooxidative Decarboxylation of Dihydrophtalates. Biochemistry 9, 344(1970). 

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