A protein containing a derivative of riboflavin, which acts as electron carrier in the electron-transport system.

Flavoproteins are proteins that contain a nucleic acid derivative of riboflavin: the flavin adenine dinucleotide (FAD) or flavin mononucleotide (FMN). These proteins act as dehydrogenation catalysts in biological reactions inside the mitochondria.

an intermediate electron transport chain carrier between NADH and ubiquinone