An enzyme containing a flavin molecule (e.g. *FMN
) as a prosthetic group. Flavoproteins are usually dehydrogenases, e.g. succinate dehydrogenase, which is a TCA cycle enzyme. The general equation for a flavoprotein reaction is: flavoprotein + reduced substrate ↔ reduced flavoprotein + oxidized substrate. Like NAD, reduced flavoproteins can be reoxidized in the *respiratory chain
. Flavoproteins are also components of the electron transport system of photosynthesis and the microsomal electron transport system.