FAD flavin-adenine
dinucleotide
(and its little brother FMN flavin mononucleotide)
accepts 2H• [or
2e- and 2H+]
basic reaction: FAD
+ SubH2 à
FADH2 + Sub
FAD is a prosthetic group tightly bound to the enzymes
that use it, including: Complexes I and II of the electron transport
system, glycerol phosphate dehydrogenase, fatty acyl-CoA dehydrogenases,
and many, many more.
Typical
reactions where FAD is utilized involve abstraction of hydrogen atoms from
two adjacent carbons, forming a C=C double bond.
Chime structures of FAD and FADH2 by
Todd Carlson at Grand Valley State University
http://faculty.gvsu.edu/carlsont/mm/proteins/flavin.html
See
another representation of FAD, FADH2, and the oxidized and reduced forms
of heme
by Thomas Terry at U Conn
http://www.sp.uconn.edu/~terry/229sp03/lectures/FADheme.html