Flavoprotein

Flavoproteins are proteins that contain a nucleic acid derivative of riboflavin: the flavin adenine dinucleotide (FAD) or flavin mononucleotide (FMN).

Flavoproteins are involved in a wide array of biological processes, including, but by no means limited to, bioluminescence, removal of radicals contributing to oxidative stress, photosynthesis, DNA repair, and apoptosis. The spectroscopic properties of the flavin cofactor make it a natural reporter for changes occurring within the active site; this makes flavoproteins one of the most-studied enzyme families.

Discovery

The first mention of a flavoprotein in the scientific literature dates back to 1879, when the work on the composition of cow’s milk resulted in the isolation of a bright-yellow pigment, that we now know as flavin, but termed lactochrome at the time. By the early 1930s, this same pigment had been isolated from a range of sources, and recognised as a component of the vitamin B complex. Its structure was determined almost simultaneously by two groups in 1934, and given the name riboflavin, derived from the ribityl side chain and yellow colour of the conjugated ring system.