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CoFactor: Flavin adenine dinucleotideGeneral information2D representation
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Molecular functionFAD is involved in both one and two electron transfer reactions [1], in radical reactions [3], as well as in photoreceptor-induced reactions [5]. Although the majority of flavin-dependant enzymes catalyse the former two types of reaction, at least two independently evolved photoprotein families have been identified, which contain photoacive flavins or pterins [5]. Chemical propertiesFAD (flavin adenine dinucleotide) is usually non-covalently bound to the apoprotein, but can also be bound covalently to the protein at 1 or 2 positions [1]. The covalent flavinylation of enzymes is a self-catalytic process [2]. Flavins can build stable semiquinone radicals under anaerobic conditions [3]. Vitamin B2 is the universal precursor of all flavo-cofactors [4]. PathwaysThe flavin biosynthetic pathway is found in plants and microorganisms [7]. The flavin-dependent enzyme glycine oxidase is involved in thiamine biosynthesis. CommentAt least four FAD-binding protein folds have been identified and each fold binds FAD with a conserved sequence motif. The four folds are represented by the four enzymes glutathione reductase, ferredoxin reductase, p-cresol methylhydroxylase and pyruvate oxidase, respectively [8]. References
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