The KTBA assay for determination of one-electron oxidation activity was used to assay reactions of low-molecular weight chelators isolated from the brown rot fungus Gloeophyllum trabeum. The assay, performed either under air or nitrogen showed that molecular oxygen was an important factor in chelator-mediated oxidation reactions. A reduction in oxidative activity was observed when superoxide dismutase was introduced to the reaction, indicating that superoxide radicals also involved in the reaction and were scavenged by SOD. The KTBA assay showed, similarly to other assays in our laboratory, that the chelators could reduce Fe(III) to Fe(II). However, once chelators were 'oxidized' in this process they appeared to be redox inactive. Preliminary results indicate that chelator redox activity can only be regenerated in the presence of a reductant such as NADH or oxalate.

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