Molecule of the Month
|Detoxification of Superoxide by a New Enzymatic Mechanism|
Superoxide (O2·−) is a biologically dangerous byproduct of cellular respiration in mitochondria. However, superoxide also serves as a first line of defense of the human immune system against bacterial invaders. We have functionally and structurally characterized a membrane protein in Escherichia coli that catalyzes a so far unknown biochemical reaction, the oxidation of superoxide to oxygen and the reduction of ubiquinone (UQ) to ubiquinol (UQ-H2).
2 O2·− + UQ + 2H+ → 2 O2 + UQ-H2
This is only the third enzyme known to specifically react with superoxide.