Evidence that a quinone may be required for the production of superoxide and hydrogen peroxide in neutrophils

Abstract

Neutrophils contain a quinone that may function as an electron carrier during production of superoxide and hydrogen peroxide. First, addition of exogenous coenzyme Q-10, coenzyme Q-6, vitamin K 1, benzoquinone or duroquinone to rat peritoneal neutrophils resulted in increased rates of oxygen consumption and increased rates of hydrogen peroxide and superoxide production. Duroquinone titration studies showed saturation kinetics at submillimolar concentrations for oxygen consumption and for hydrogen peroxide and superoxide production. Second, tropolone, 2-hydroxy-2,4,6-cycloheptatrienone, effectively inhibited oxygen metabolism in neutrophils perhaps because of its structural similarity to quinone. Dibromothymoquinone, a known inhibitor at the quinone level in chloroplasts and mitochondria, was also inhibitory in neutrophils.