Succinate Dehydrogenase

Succinate dehydrogenase (also called succinate-coenzyme Q reductase or Complex II) is an enzyme of the citric acid cycle and glyoxylate cycle, that catalyzes the reaction below:

> Succinate + FAD (enzyme bound) <=> Fumarate + FADH 2 (enzyme bound) ( = 0)

In the reaction, a trans double bond is formed, with transfer of the two hydrogens to FAD, forming FADH 2.

FAD is bound covalently to the enzyme protein through a specific histidine residue. Succinate dehydrogenase is tightly bound to the mitochondrial inner membrane. The importance of this binding is that the reduced flavin, which must be reoxidized for the enzyme to act again, becomes reoxidized through interaction with the mitochondrial electron transport system, also bound to the membrane.

Succinate dehydrogenase is inhibited by malonate.

Next enzyme of citric acid cycle / Previous enzyme of citric acid cycle

See also: Citric Acid Cycle Enzymes, Table 14.1

INTERNET LINKS:

> 1. Glyoxylate Cycle Metabolism

> 2. Citric Acid Cycle