flavin adenine dinucleotide

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Related to flavin adenine dinucleotide: flavin mononucleotide, nicotinamide adenine dinucleotide

flavin adenine dinucleotide

(FAD): see coenzymecoenzyme
, any one of a group of relatively small organic molecules required for the catalytic function of certain enzymes. A coenzyme may either be attached by covalent bonds to a particular enzyme or exist freely in solution, but in either case it participates intimately in
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The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Flavin Adenine Dinucleotide


(FAD; also riboflavin-5’-adenosine diphosphate), a nonprotein component (coenzyme) of most flavoproteins, which are present in all living cells; a derivative of riboflavin. Molecular wieght, 785.56.

FAD participates in the oxidation-reduction processes of organisms. It is soluble in water and organic solvents and is characterized by intensive fluorescence, with a maximum emission between 520 and 540 nanometers. In a number of cases, it exhibits strong covalent bonding with proteins (for example, in mono-amine oxidase); in some instances, it is capable of dissociating from an apoenzyme similar to nicotinamide adenine dinucleotide. Its catalytic activity is related to the capacity of nitrogen atoms in the FAD molecule’s isoalloxazine ring to affix two hydrogen atoms from the oxidized substrate. This process occurs in two stages, with the formation of the intermediate product semiquinone, which contains a nitrogen atom with an unshared electron. The oxidation-reduction potential of FAD depends on the nature of the apoenzyme; it changes from – 0.06 volt (at pH 7.0) for the free form of FAD to –0.185 volt for several flavoproteins. FAD biosynthesis is brought about by flavin mononucleotide (FMN) and adenosine triphosphate (ATP) with the participation of the enzyme adenylil transferase.

The acronym FAD is widely used in the biological literature.


The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.

flavin adenine dinucleotide

[′fla·vən ′ad·ən‚ēn dī′nü·klē·ə‚tīd]
C27H33N9O15P2 A coenzyme that functions as a hydrogen acceptor in aerobic dehydrogenases (flavoproteins). Abbreviated FAD.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
Reducing equivalents of NADH (reduced nicotinamide adenine dinucleotide), NADPH (reduced nicotinamide adenine dinucleotide phosphate), and FAD[H.sub.2] (reduced flavin adenine dinucleotide) generated under aerobic conditions via glycolysis, the Krebs cycle, and [beta]-oxidation pathways could be reoxidized efficiently through the electron-transport chain, terminating with oxygen.
Abbreviations COX-2: Cyclooxygenase-2 FAD: Flavin adenine dinucleotide H[O.sup.*]: Hydroxyl radical [H.sub.2][O.sub.2]: Hydrogen peroxide Mo-co: Molybdenum-containing molybdopterin cofactor [NAD.sup.+]: Oxidized nicotinamide adenine dinucleotide NADH: Reduced nicotinamide adenine dinucleotide NF-[kappa]B: Nuclear factor kappa-light-chain-enhancer of activated B cells NO: Nitric oxide ONO[O.sup.-]: Peroxynitrite RNS: Reactive nitrogen species ROS: Reactive oxygen species [O.sub.2]: Molecular oxygen [O.sub.2.sup.*-]: Superoxide anion XDH: Xanthine dehydrogenase XO: Xanthine oxidase XOR: Xanthine oxidoreductase.
Comment: Flavin adenine dinucleotide (FAD), a riboflavin-containing molecule, is the cofactor for MTHFR.