FAD

(flavin adenine dinucleotide) A riboflavin-derived coenzyme that acts as a prosthetic   group   to   several   dehydrogenase    enzymes,    accepting    electrons from  the  substrate and  thus being reduced to FADH₂. The most important FAD-linked  enzymes  are  succinate  dehydrogenase, which oxidizes succinate to fumarate,   and   dihydrolipoyl   dehydrogenase, a component of the pyruvate dehydrogenase   complex,   which   oxidizes pyruvate to acetyl CoA. See also flavoprotein.