Direct enzymatic reduction of lucigenin decreases lucigenin-amplified chemiluminescence produced by superoxide ion

The interaction of superoxide ion with lucigenin produces chemiluminescence (CL), which is widely used for the detection of this radical anion. However, in many biological systems lucigenin may be directly reduced to its semiquinone by some enzymes. We found that if the direct reduction of lucigenin takes place, it decreases superoxide production due to the competition with one-electron reduction of dioxygen to superoxide ion. Comparison of two methods of superoxide detection (lucigenin-amplified CL and cytochrome c reduction) showed that there are excellent correlations between the results obtained by the two methods. Hence, lucigenin-amplified CL remains a sensitive and reliable assay of superoxide detection. Copyright (C) 2001 John Wiley & Sons, Ltd.