Alloxazine mononucleotide

This structure is quite analogous to that of the pyrimidine nucleotide anhydrides mentioned above. FAD, which also contains a pyrophosphate bond, is converted by alkali into an alloxazine mononucleotide with doubly esterified phosphate at carbons 4 and 5 of the ribityl moiety. 

The flavoproteins, or yellow enzymes, have been shown to contain either alloxazine mononucleotide (flavin mononucleotide, FMN) or isoalloxazine adenine dinucleotide (flavin adenine dinucleotide, FAD) (Fig. 6). The... 

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