The enhancement of iron-dependent luminol peroxidation by 2,2'-dipyridyl and nitrilotriacetate

The generation of radicals from luminol and H2O2, in the presence of iron and iron chelates was monitored by measuring the chemiluminescence produced by further oxidation of these radicals. 2,2'-Dipyridyl enhanced the production of chemiluminescence in the presence of FeSO4, ferritin and haemosiderin but not FeCl3 or horseradish peroxidase. Nitrilotriacetic acid (NTA) enhanced chemiluminescence in the presence of both FeSO4 and FeCl3 but not ferritin or haemosiderin. The enhancement of chemiluminescence by iron chelation may have analytical applications and the process by which these iron chelates are able to generate radicals from the nitrogenous base luminol may be similar to that responsible for their toxic effects on DNA.