Editing Dehydrogenase (section)

=== Transferring two hydrogens ===
[[File:Krebs_cycle_6_succinate_to_fumarate.svg|thumb|Reaction catalyzed by succinate dehydrogenase, note the double bond formed between the two central carbons when two hydrogens are removed]]
In the above case, the dehydrogenase has transferred a hydride while releasing a proton, H<sup>+</sup>, but dehydrogenases can also transfer two hydrogens, using FAD as an electron acceptor. This would be depicted as AH<sub>2</sub> + B ↔ A + BH<sub>2</sub>.
A double bond is normally formed in between the two atoms that the hydrogens were taken from, as in the case of [[succinate dehydrogenase]]. The two hydrogens have been transferred to the carrier or the other product, with their electrons.