Succinate Dehydrogenase Complex II and its Inhibitors

Complex II is the succinate dehydrogenase of the tricarboxylic acid, or Krebs, cycle and catalyzes the oxidation of succinate to fumarate, coupled to the reduction of UQ to ubiquinol. It is part of a large family of related succinate quinone oxidoreductases and quinol fumarate oxidoreductases found in bacteria and mitochondria that have been classified based on subunit structure, number of cytochrome b haem centers and class of quinone substrate [77, 78]. The mitochondrial form belongs to the class that has a single h type haem bound to one of 

Fungicidal inhibitors of Complex II are discussed in Chapter 13.3 of this volume. Recently, the novel acaricide Cyenopyrafen, which is structurally related to an earlier insecticide [93], has been reported to act by potent inhibition of Complex II after hydrolysis of the t-butyl ester (Table 13.1.3) [94]. 

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