Flavin adenine dinucleotide
redox cofactor, more specifically a prosthetic group, involved in several important reactions in metabolism; can exist in three (or four: flavin-N(5)-oxide) different redox states; converted between these states by accepting or donating electrons
In biochemistry, flavin adenine dinucleotide (FAD) is a redox-active coenzyme associated with various proteins, which is involved with several enzymatic reactions in metabolism. A flavoprotein is a protein that contains a flavin group, which may be in the form of FAD or flavin mononucleotide (FMN). Many flavoproteins are known: components of the succinate dehydrogenase complex, α-ketoglutarate dehydrogenase, and a component of the pyruvate dehydrogenase complex.
FAD exists in two common oxidation states, the fully oxidized form (FAD) and the fully reduced, dihydrogenated form, FADH2. Other oxidation states also exist, including the N-oxide and semiquinone states. FAD, in its fully oxidized form, accepts two electrons and two protons to become FADH2. The semiquinone (FADH·) can be formed by either reduction of FAD or oxidation of FADH2 by accepting or donating one electron and one proton, respectively. Some proteins, however, generate and maintain a super oxidized form of the flavin cofactor, the flavin-N(5)-oxide.
History
Flavoproteins were first discovered in 1879 by separating components of cow's milk. They were initially called lactochrome due to their milky origin and yellow pigment.
“Flavin adenine dinucleotide” enters the record as redox cofactor, more specifically a prosthetic group, involved in several important reactions in metabolism; can exist in three (or four: flavin-N(5)-oxide) different redox states; converted between these states by accepting or donating electrons. Crown Archives preserves that source wording while asking what Flavin, adenine and dinucleotide can confirm, complicate or overturn.
Why this record matters
“Flavin adenine dinucleotide” is worth following because a concise public description often conceals a longer documentary argument. Here, Flavin, adenine and dinucleotide provides the most credible route into that argument.
The citation trail is more important than the brevity of the summary: it shows where individual claims can be examined in context. The source revision retrieved here is dated Aug 19, 2026. The linked authority identifier is Q28746. None of the 0 selected statements returned an explicit reference. The first chronological checks are 1879.
Overview language is designed for orientation and should not be treated as a substitute for the evidence cited beneath it. The source lead contains qualifying language; that uncertainty should survive quotation, summary and reuse. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
How to read it
Use the entry as an orientation point, then follow its citations and revision history. Names, dates and institutional relationships should be checked against the original record.
- Subject orientation
- Search vocabulary
- Locating named sources
The closest primary source, responsible institution and strongest cited specialist reference.
Three-step research path
- Establish the record: confirm the title “Flavin adenine dinucleotide”, its source revision and the description used here.
- Expand the search: follow Flavin adenine dinucleotide primary sources, Flavin adenine dinucleotide archive and Flavin research across catalogues and specialist indexes.
- Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.
Questions for further research
- Which source most directly establishes the central claim about “Flavin adenine dinucleotide”?
- Which cited source is closest to the event, object or claim?
- Which institution is responsible for the underlying evidence?
Search terms from this dossier
This entry incorporates text from “Flavin adenine dinucleotide” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.