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. 2006 Apr 11;2006:31372. doi: 10.1155/JBB/2006/31372

Figure 1.

Figure 1

Illustration of sites of free radical generation in the mitochondria. In the respiratory chain, complexes 1 and 3 leak electrons to oxygen, producing primarily superoxide radicals (or O2•−). The O2•− are dismutated by manganese superoxide dismutase to generate H2O2 and oxygen. Complex 1 generates O2•− only toward the matrix. Complex 3, on the other hand, generates O2•− toward both the intermembrane space and the matrix. The components of tricarboxylic acid, including α-ketoglutarate dehydrogenase, also generate O2•− in the matrix. Free radicals are generated in the outer mitochondrial membrane (monoamine oxidase) and catalyze the oxidative deamination of primary aromatic amines, leading to the generation of H2O2.