In
biochemistry,
flavin adenine dinucleotide (
FAD) is a
redox cofactor, more specifically a
prosthetic group, involved in several important reactions in
metabolism. FAD can exist in three (or four: flavin-N(5)-oxide) different redox states, which are the quinone, semiquinone, and hydroquinone. FAD is converted between these states by accepting or donating electrons.